configs/mirtoo README
=====================

This README file discusses the port of NuttX to the DTX1-4000L "Mirtoo" module.
This module uses MicroChip PIC32MX250F128D and the Dimitech DTX1-4000L EV-kit1
V2. See http://www.dimitech.com/ for further information.

Contents
========

  PIC32MX250F128D Pin Out
  Toolchains
  Loading NuttX with ICD3
  LED Usage
  UART Usage
  Analog Input
  PIC32MX Configuration Options
  Configurations

PIC32MX250F128D Pin Out
=======================

PIC32MX250F128D 44 pin package.

PIN PIC32 SIGNAL(s)                                  BOARD SIGNAL/USAGE                  EV-Kit1 CONNECTION
--- ------------------------------------------------ ---------------------------------- ----------------------------------
 1  RPB9/SDA1/CTED4/PMD3/RB9                         FUNC3                              FUNC3, to X3, pin3
    RPB9      Peripheral pin selection RB9
    SDA1      I2C1 data
    CTED4     CTMU External Edge Input 4
    PMD3      Parallel Master Port data bit 3
    RB9       PORTB, Pin 9
--- ------------------------------------------------ ---------------------------------- ----------------------------------
 2  RPC6/PMA1/RC6                                    FUNC5                              FUNC5, to X3, pin5
    RPC6      Peripheral pin selection RC6
    PMA1      Parallel Master Port Address bit 1
    RC6       PORTC, Pin 6
--- ------------------------------------------------ ---------------------------------- ----------------------------------
 3  RPC7/PMA0/RC7                                    PEN, PGA117 ENA pin                Not available off module
    RPC7      Peripheral pin selection RC7           Not available
    PMA0      Parallel Master Port Address bit 0     Not available
    RC7       PORTC, Pin 7                           Used for PGA117 ENA output
--- ------------------------------------------------ ---------------------------------- ----------------------------------
 4  RPC8/PMA5/RC8                                    LED0                               Not available off module
    RPC8      Peripheral Selection, PORTC, Pin 8     Not available
    PMA5      Parallel Master Port Address bit 5     Not available
    RC8       PORTC, Pin 8                           Used to drive LED0
--- ------------------------------------------------ ---------------------------------- ----------------------------------
 5  RPC9/CTED7/PMA6/RC9                              LED1                               Not available off module
    RPC9      Peripheral Selection, PORTC, Pin 9     Not available
    CTED7     CTMU External Edge Input 7             Not available
    PMA6      Parallel Master Port Address bit 6     Not available
    RC9       PORTC, Pin 9                           Used to drive LED1
--- ------------------------------------------------ ---------------------------------- ----------------------------------
 6  VSS                                              VSS                                Not available off module
--- ------------------------------------------------ ---------------------------------- ----------------------------------
 7  VCAP                                             VCAP                               Not available off module
--- ------------------------------------------------ ---------------------------------- ----------------------------------
 8  PGED2/RPB10/D+/CTED11/RB10                       FUNC0                              FUNC0, to FT230XS RXD and debug port
    PGED2    Debug Channel 2 data                                                       Used at boot time for ICD3
    RPB10    Peripheral Selection, PORTB, Pin 10                                        Used for UART RXD
    D+       USB D+                                                                     Not available
    CTED11   CTMU External Edge Input 11                                                Not available
    RB10     PORTB, Pin 10                                                              Not available
--- ------------------------------------------------ ---------------------------------- ----------------------------------
 9  PGEC2/RPB11/D-/RB11                              FUNC1                              FUNC1, to FT230XS TXD
    PGEC2    Debug Channel 2 clock                                                      Used at boot time for ICD3
    RPB11    Peripheral Selection, PORTB, Pin 11                                        Used for UART TXD
    D-       USB D-                                                                     Not available
    RB11     PORTB, Pin 11                                                              Not available
--- ------------------------------------------------ ---------------------------------- ----------------------------------
10  VUSB3V3                                          3.3V                               (via VBAT, Pin 1)
    VUSB3V3  USB internal transceiver supply         3.3V
--- ------------------------------------------------ ---------------------------------- ----------------------------------
11  AN11/RPB13/CTPLS/PMRD/RB13                       ~CSM SST25VF3032B Chip Select      Not available off-module
    AN11     Analog input channel 11                 Not available
    RPB13    Peripheral Selection, PORTB, Pin 12     Not available
    CTPLS    CTMU Pulse Output                       Not available
    PMRD     Parallel Master Port read strobe        Not available
    RB13     PORTB, Pin 12                           Used for SST25VF3032B Chip Select
--- ------------------------------------------------ ---------------------------------- ----------------------------------
12  PGED/TMS/PMA10/RA10                              DIN5                               PORT5, to X7, pin 2
    PGED4    Debug Channel 4 data                    (?)                                 (also X13, pin6)
    TMS      JTAG Test mode select pin               (?)
    PMA10    Parallel Master Port Address bit 10     Not available
    RA10     PORTA, Pin 10                           May be used as GPIO input
--- ------------------------------------------------ ---------------------------------- ----------------------------------
13  PGEC/TCK/CTED8/PMA7/RA7                          DIN2                               PORT2, to X4, pin 2
    PGEC4    Debug Channel 4 clock                   Not available                       (also X13, pin5)
    TCK      JTAG test clock input pin               May be used as JTAG clock input
    CTED8    CTMU External Edge Input 8              May be used as CTMU input
    PMA7     Parallel Master Port Address bit 7      Not available
    RA7      PORTA, Pin 7                            May be used as GPIO input
--- ------------------------------------------------ ---------------------------------- ----------------------------------
14  CVREF/AN10/C3INB/RPB14/VBUSON/SCK1/CTED5/RB14    FUNC5 (through resistor)           FUNC5, to X3, pin5
    CVREFOUT Comparator Voltage Reference output
    AN10     Analog input channel 10
    C3INB    Comparator 3 Input B
    RPB14    Peripheral Selection, PORTB, Pin 14
    VBUSON   USB Host and OTG bus power control
    SCK1     SPI1 clock
    CTED5    CTMU External Edge Input 5
    RB14      PORTB, Pin 14
--- ------------------------------------------------ ---------------------------------- ----------------------------------
15  AN9/C3INA/RPB15/SCK2/CTED6/PMCS1/RB15            SCK                                Not available off module
    AN9      Analog input channel 9                  Not available
    C3INA    Comparator 3 Input A                    Not available
    RPB15    Peripheral Selection, PORTB, Pin 15     Not available
    SCK2     SPI2 clock                              Used for SPI2 clock
    CTED6    CTMU External Edge Input 6              Not available
    PMCS1    Parallel Master Port Chip Select 1      Not available
    RB15     PORTB, Pin 15                           Not available
--- ------------------------------------------------ ---------------------------------- ----------------------------------
16  AVSS                                             AVSS                               Not available off module
--- ------------------------------------------------ ---------------------------------- ----------------------------------
17  AVDD                                             AVDD                               Not available off module
--- ------------------------------------------------ ---------------------------------- ----------------------------------
18  ~MCLR                                            ~MCLR, TC2030-NL, pin 1            Not available off module
--- ------------------------------------------------ ---------------------------------- ----------------------------------
19  PGED3/VREF+/CVREF+/AN0/C3INC/RPA0/CTED1/PMD7/RA0 AIN PGA117 Vout
    AN0      Analog input channel 0                  AIN
    RA0      PORTA, Pin 0                            Not available
    CVREF+   Comparator Voltage Reference (high)     (?)
    C3INC    Comparator 3 Input C                    (?)
    PMD7     Parallel Master Port data bit 7         Not available
    CTED1    CTMU External Edge Input 1              Not available
    PGED3    Debug Channel 3 data                    Not available
    VREF+    Analog voltage reference (high)         Not available
--- ------------------------------------------------ ---------------------------------- ----------------------------------
20  PGEC3/VREF-/CVREF-/AN1/RPA1/CTED2/PMD6/RA1       SI                                 Not available off module
    PGEC3    Debug Channel 3 clock                   Not available
    VREF-    Analog voltage reference (low)          Not available
    CVREF-   Comparator Voltage Reference (low)      Not available
    AN1      Analog input channel 1                  Not available
    RPA1     Peripheral Selection PORTA, Pin 1       Used for SI
    CTED2    CTMU External Edge Input 2              Not available
    PMD6     Parallel Master Port data bit 6         Not available
    RA1      PORTA, Pin 1                            Not available
--- ------------------------------------------------ ---------------------------------- ----------------------------------
21  PGED1/AN2/C1IND/C2INB/C3IND/RPB0/PMD0/RB0        DIN6                               PORT6, to X9, pin 2
    PGED1    Debug Channel 1 data                    Not available                       (also X13, pin4)
    AN2      Analog input channel 2                  Not available (digital input only)
    C1IND    Comparator 1 Input D                    Not available (digital input only)
    C2INB    Comparator 2 Input B                    Not available (digital input only)
    C3IND    Comparator 3 Input D                    Not available (digital input only)
    RPB0     Peripheral Selection PORTB, Pin 0       May be used for peripheral input
    PMD0     Parallel Master Port data bit 0         Not available
    RB0      PORTB, Pin 0                            May be used for GPIO input
--- ------------------------------------------------ ---------------------------------- ----------------------------------
22  PGEC1/AN3/C1INC/C2INA/RPB1/CTED12/PMD1/RB1       DIN7                               PORT7, to X10, pin 2
    PGEC1    Debug Channel 1 clock                   (?)                                 (also X13, pin2)
    AN3      Analog input channel 3                  Not available (digital input only)
    C1INC    Comparator 1 Input C                    Not available (digital input only)
    C2INA    Comparator 2 Input A                    Not available (digital input only)
    RPB1     Peripheral Selection, PORTB, Pin 1      May be used for peripheral input
    PMD1     Parallel Master Port data bit 1         Not available
    CTED12   CTMU External Edge Input 12             May be used as CTMU input
    RB1      PORTB, Pin 1                            May be used as GPIO input
--- ------------------------------------------------ ---------------------------------- ----------------------------------
23  AN4/C1INB/C2IND/RPB2/SDA2/CTED13/PMD2/CNB2/RB2   DOUT0                              PORT0, to X1, pin 2
    AN4      Analog input channel 4                  Not available (digital output only) (also X13, pin1)
    C1INB    Comparator 1 Input B                    Not available (digital output only)
    C2IND    Comparator 2 Input D                    Not available (digital output only)
    RPB2     Peripheral Selection PORTB, Pin 2       May be used for peripheral output
    SDA2     I2C2 data                               Not available(?)
    CTED13   CTMU External Edge Input 13             Not available
    PMD2     Parallel Master Port data bit 2         Not available
    CNB2     PORTB, Pin 2 Change Notification        Not available
    RB2      PORTB, Pin 2                            May be for GPIO output
--- ------------------------------------------------ ---------------------------------- ----------------------------------
24  AN5/C1INA/C2INC/RTCC/RPB3/SCL2/PMWR/CNB3/RB3     DOUT1                              PORT1, to X2, pin 2
    AN5      Analog input channel 5                  Not available (digital output only) (also X13, pin3)
    C1INA    Comparator 1 Input A                    Not available (digital output only)
    C2INC    Comparator 2 Input C                    Not available (digital output only)
    RTCC     Real-Time Clock alarm output            May be used for RTCC output
    RPB3     Peripheral Selection, PORTB, Pin 3      May be used for peripheral output
    SCL2     I2C2 clock                              (?)
    PMWR     Parallel Master Port write strobe       Not available
    CNB3     PORTB, Pin 3 Change Notification        Not available
    RB3      PORTB, Pin 3                            May be used for GPIO output
--- ------------------------------------------------ ---------------------------------- ----------------------------------
25  AN6/RPC0/RC0                                     DOUT3                              PORT3, to X5, pin 2
    AN6      Analog input channel 6                  Not available (digital output only) (also X13, pin7)
    RPC0     Peripheral Selection, PORTC, Pin 0      May be used for peripheral output
    RC0      PORTC, Pin 0                            May be used for GPIO output
--- ------------------------------------------------ ---------------------------------- ----------------------------------
26  AN7/RPC1/RC1                                     DOUT4                              PORT4, to X6, pin 2
    AN7      Analog input channel 7                  Not available (digital output only) (also X13, pin8)
    RPC1     Peripheral Selection, PORTC, Pin 1      May be used for peripheral output
    RC1      PORTC, Pin 1                            May be used for GPIO output
--- ------------------------------------------------ ---------------------------------- ----------------------------------
27  AN8/RPC2/PMA2/RC2                                DOUT5                              PORT5, to X7, pin 2
    AN8      Analog input channel 8                  Not available (digital output only) (also X13, pin6)
    RPC2     Peripheral Selection, PORTC, Pin 2      May be used for peripheral output
    PMA2     Parallel Master Port Address bit 2      Not available
    RC2      PORTC, Pin 2                            May be used for GPIO output
--- ------------------------------------------------ ---------------------------------- ----------------------------------
28  VDD                                              VDD                                Not available off module
--- ------------------------------------------------ ---------------------------------- ----------------------------------
29  VSS                                              VSS                                Not available off module
--- ------------------------------------------------ ---------------------------------- ----------------------------------
30  OSC1/CLKI/RPA2/RA2                               SO (R1) DIN0 (R2)                  Not available off module
    OSC1     Oscillator crystal input                Not available
    CLKI     External clock source input             Not available
    RPRA2    Peripheral Selection PORTA, Pin 2       Used for SO
    RA2      PORTA, Pin 2                            Not available
--- ------------------------------------------------ ---------------------------------- ----------------------------------
31  OSC2/CLKO/RPA3/RA3                               DIN0 (R1) DIN3 (R2)                PORT0, to X1, pin 2
    OSC2     Oscillator crystal output               Not available                       (also X13, pin1)
    CLKO     Oscillator crystal output               Not available
    RPA3     Peripheral Selection for PORTA, Pin 3   May be used for peripheral input
    RA3      PORTA, Pin 3                            May be used for GPIO input
--- ------------------------------------------------ ---------------------------------- ----------------------------------
32  TDO/RPA8/PMA8/RA8                                DIN3 (R1) S0 (R2)                  PORT3, to X5, pin 2
    TDO      JTAG test data output pin               Not available                       (also X13, pin7)
    RPA8     PORTA, Pin 8                            May be used for peripheral input
    PMA8     Parallel Master Port Address bit 8      Not available
    RA8      PORTA, Pin 8                            May be used for GPIO input
--- ------------------------------------------------ ---------------------------------- ----------------------------------
33  SOSCI/RPB4/RB4                                   DOUT2                              PORT2, to X4, pin 2
    SOSCI    32.768 kHz crystal input                Not available                       (also X13, pin5)
    RPB4     Peripheral Seclection, PORTB, Pin 4     May be used for peripheral output
    RB4      PORTB, Pin 4                            May be used for GPIO output
--- ------------------------------------------------ ---------------------------------- ----------------------------------
34  SOSCO/RPA4/T1CK/CTED9/RA4                        DIN1                               PORT1, to X2, pin 2
    SOSCO    32.768 kHz crystal output               Not available                       (also X13, pin3)
    RPA4     Peripheral Selection PORTA, Pin 4       May be used for peripheral input
    T1CK     Timer1 external clock input             May be used for timer 1 input
    CTED9    CTMU External Edge Input 9              May be used for CTMU input
    RA4      PORTA, Pin 4                            May be used as GPIO input
--- ------------------------------------------------ ---------------------------------- ----------------------------------
35  TDI/RPA9/PMA9/RA9                                DIN4                               PORT4, to X6, pin 2
    TDI      JTAG test data input pin                May be used for JTAG input          (also X13, pin8)
    RPA9     Peripheral Selection for PORTA, Pin 9   May be used for peripheral input
    PMA9     Parallel Master Port Address bit 9      Not available
    RA9      PORTA, Pin 9                            May be used for GPIO input
--- ------------------------------------------------ ---------------------------------- ----------------------------------
36  AN12/RPC3/RC3                                    DOUT6                              PORT6, to X9, pin 2
    AN12     Analog input channel 12                 Not available (digtial output only) (also X13, pin4)
    RPC3     Peripheral Selection, PORTC, Pin 3      May be used for peripheral output
    RC3      PORTC, Pin 3                            May be used for GPIO output
--- ------------------------------------------------ ---------------------------------- ----------------------------------
37  RPC4/PMA4/RC4                                    DOUT7                              PORT7, to X10, pin 2
    RPC4     Peripheral Selection, PORTC, Pin 4      May be used for peripheral output   (also X13, pin2)
    PMA4     Parallel Master Port Address bit 4      Not available
    RC4      PORTC, Pin 4                            May be used for GPIO output
--- ------------------------------------------------ ---------------------------------- ----------------------------------
38  RPC5/PMA3/RC5                                    FUNC4                              FUNC4, to X3, pin4
    RPC5     Peripheral Selection, PORTC, Pin 5
    PMA3     Parallel Master Port Address bit 3
    RC5      PORTC, Pin 5
--- ------------------------------------------------ ---------------------------------- ----------------------------------
39  VSS                                              VSS                                Not available off module
--- ------------------------------------------------ ---------------------------------- ----------------------------------
40  VDD                                              VDD                                Not available off module
--- ------------------------------------------------ ---------------------------------- ----------------------------------
41  RPB5/USBID/RB5                                   FUNC3                              FUNC3, to X3, pin3
    RPB5     Peripheral Selection, PORTB, Pin 5
    USBID    41  USB OTG ID detect
    RB5      41  PORTB, Pin 5
--- ------------------------------------------------ ---------------------------------- ----------------------------------
42  VBUS                                             FUNC2                              FUNC2, to X3, pin2
    VBUS     Analog USB bus power monitor
--- ------------------------------------------------ ---------------------------------- ----------------------------------
43  RPB7/CTED3/PMD5/INT0/RB7                         PGA117 ~CSAI                       Not available off module
    RPB7     Peripheral Selection, PORTB, Pin 7
    CTED3    CTMU External Edge Input 3
    PMD5     Parallel Master Port data bit 5
    INT0     External Interrupt 0
    RB7      PORTB, Pin 7
--- ------------------------------------------------ ---------------------------------- ----------------------------------
44  RPB8/SCL1/CTED10/PMD4/RB8                        FUNC2                              FUNC2
    RPB8     PORTB, Pin 8
    SCL1     I2C1 clock
    CTED10   CTMU External Edge Input 10
    PMD4     Parallel Master Port data bit 4
    RB8      PORTB, Pin 8
--- ------------------------------------------------ ---------------------------------- ----------------------------------

Additional signals available via Peripheral Pin Selections (PPS)
----------------------------------------------------------------

  REFCLKI  Reference Input Clock
  REFCLKO  Reference Output Clock
  IC1      Capture Inputs 1
  IC2      Capture Inputs 2
  IC3      Capture Inputs 3
  IC4      Capture Inputs 4
  IC5      Capture Inputs 5
  OC1      Output Compare Output 1
  OC2      Output Compare Output 2
  OC3      Output Compare Output 3
  OC4      Output Compare Output 4
  OC5      Output Compare Output 5
  OCFA     Output Compare Fault A Input
  OCFB     Output Compare Fault B Input
  INT1     External Interrupt 1
  INT2     External Interrupt 2
  INT3     External Interrupt 3
  INT4     External Interrupt 4
  T2CK     Timer2 external clock input
  T3CK     Timer3 external clock input
  T4CK     Timer4 external clock input
  T5CK     Timer5 external clock input
  U1CTS    UART1 clear to send
  U1RTS    UART1 ready to send
  U1RX     UART1 receive
  U1TX     UART1 transmit
  U2CTS    UART2 clear to send
  U2RTS    UART2 ready to send
  U2RX     UART2 receive
  U2TX     UART2 transmit
  SDI1     SPI1 data in
  SDO1     SPI1 data out
  SS1      SPI1 slave synchronization or frame pulse I/O
  SDI2     SPI2 data in
  SDO2     SPI2 data out
  SS2      SPI2 slave synchronization or frame pulse I/O
  C1OUT    Comparator 1 Output
  C2OUT    Comparator 2 Output
  C3OUT    Comparator 3 Output

Toolchains
==========

  Note that in addition to the configuration options listed below, the
  toolchain can be configured using the kconfig-mconf utility ('make menuconfig')
  or by passing CONFIG_MIPS32_TOOLCHAIN=<toolchain> to make, where
  <toolchain> is one of GNU_ELF, MICROCHIPL, MICROCHIPW, MICROCHIPL_LITE,
  MICROCHIPW_LITE, MICROCHIPOPENL or PINGUINOW as described below.

  MPLAB/C32
  ---------

  I am using the free, "Lite" version of the PIC32MX toolchain available
  for download from the microchip.com web site.  I am using the Windows
  version.  The MicroChip toolchain is the only toolchain currently
  supported in these configurations, but it should be a simple matter to
  adapt to other toolchains by modifying the Make.defs file include in
  each configuration.

  Toolchain Options:

    CONFIG_PIC32MX_MICROCHIPW      - MicroChip full toolchain for Windows (C32)
    CONFIG_PIC32MX_MICROCHIPL      - MicroChip full toolchain for Linux (C32)
    CONFIG_PIC32MX_MICROCHIPW_LITE - MicroChip LITE toolchain for Windows (C32)
    CONFIG_PIC32MX_MICROCHIPL_LITE - MicroChip LITE toolchain for Linux (C32)

  NOTE:  The "Lite" versions of the toolchain does not support C++.  Also
  certain optimization levels are not supported by the Lite toolchain.

  MicrochipOpen
  -------------

  An alternative, build-it-yourself toolchain is available here:
  http://sourceforge.net/projects/microchipopen/ .  These tools were
  last updated circa 2010.  NOTE:  C++ support still not available
  in this toolchain.  Use this configuration option to select the microchipopen
  toolchain:

    CONFIG_PIC32MX_MICROCHIPOPENL - microchipOpen toolchain for Linux

  And set the path appropriately in the setenv.sh file.

  Building MicrochipOpen (on Linux)
  ---------------------------------

  1) Get the build script from this location:

      http://microchipopen.svn.sourceforge.net/viewvc/microchipopen/ccompiler4pic32/buildscripts/trunk/

  2) Build the code using the build script, for example:

      ./build.sh -b v105_freeze

     This will check out the selected branch and build the tools.

  3) Binaries will then be available in a subdirectory with a name something like
     pic32-v105-freeze-20120622/install-image/bin (depending on the current data
     and the branch that you selected.

     Note that the tools will have the prefix, mypic32- so, for example, the
     compiler will be called mypic32-gcc.

  Pinguino mips-elf / Generic mips-elf Toolchain
  ---------------------------

  Another option is the mips-elf toolchain used with the Pinguino project.  This
  is a relatively current mips-elf GCC and should provide free C++ support as
  well. This toolchain can be downloded from the Pinguino website:
  http://wiki.pinguino.cc/index.php/Main_Page#Download . There is some general
  information about using the Pinguino mips-elf toolchain in this thread:
  http://tech.groups.yahoo.com/group/nuttx/message/1821

  Support for the Pinguino mips-elf toolchain has been included in the Mirtoo
  configurations.  Use one of these configuration options to select the Pinguino
  mips-elf toolchain:

    CONFIG_PIC32MX_PINGUINOW        - Pinguino mips-elf toolchain for Windows
    CONFIG_MIPS32_TOOLCHAIN_GNU_ELF - mips-elf toolchain for Linux or OS X

  And set the path appropriately in the setenv.sh file.  These tool configurations
  are untested -- expect some additional integration issues.  Good luck!

  This configuration will also work with any generic mips-elf GCC past version
  4.6 or so.

  MPLAB/C32 vs MPLABX/X32
  -----------------------

  It appears that Microchip is phasing out the MPLAB/C32 toolchain and replacing
  it with MPLABX and XC32.  At present, the XC32 toolchain is *not* compatible
  with the NuttX build scripts.  Here are some of the issues that I see when trying
  to build with XC32:

  1) Make.def changes:  You have to change the tool prefix:

     CROSSDEV=xc32-

  2) debug.ld/release.ld:  The like expect some things that are not present in
     the current linker scripts (or are expected with different names).  Here
     are some partial fixes:

     Rename:  kseg0_progmem to kseg0_program_mem
     Rename:  kseg1_datamem to kseg1_data_mem

  Even then, there are more warnings from the linker and some undefined symbols
  for non-NuttX code that resides in the unused Microchip libraries.  See this
  email thread at http://tech.groups.yahoo.com/group/nuttx/message/1458 for more
  information.  You will have to solve at least this undefined symbol problem if
  you want to used the XC32 toolchain.

  Windows Native Toolchains
  -------------------------

  NOTE:  There are several limitations to using a Windows based toolchain in a
  Cygwin environment.  The three biggest are:

  1. The Windows toolchain cannot follow Cygwin paths.  Path conversions are
     performed automatically in the Cygwin makefiles using the 'cygpath' utility
     but you might easily find some new path problems.  If so, check out 'cygpath -w'

  2. Windows toolchains cannot follow Cygwin symbolic links.  Many symbolic links
     are used in Nuttx (e.g., include/arch).  The make system works around these
     problems for the Windows tools by copying directories instead of linking them.
     But this can also cause some confusion for you:  For example, you may edit
     a file in a "linked" directory and find that your changes had no effect.
     That is because you are building the copy of the file in the "fake" symbolic
     directory.  If you use a Windows toolchain, you should get in the habit of
     making like this:

       make clean_context all

     An alias in your .bashrc file might make that less painful.

  3. Dependencies are not made when using Windows versions of the GCC.  This is
     because the dependencies are generated using Windows pathes which do not
     work with the Cygwin make.

       MKDEP                = $(TOPDIR)/tools/mknulldeps.sh

Loading NuttX with ICD3
========================

  Intel Hex Forma Files:
  ----------------------

    When NuttX is built it will produce two files in the top-level NuttX
    directory:

    1) nuttx - This is an ELF file, and
    2) nuttx.hex - This is an Intel Hex format file.  This is controlled by
       the setting CONFIG_INTELHEX_BINARY in the .config file.

    The PICkit tool wants an Intel Hex format file to burn into FLASH. However,
    there is a problem with the generated nutt.hex: The tool expects the nuttx.hex
    file to contain physical addresses.  But the nuttx.hex file generated from the
    top-level make will have address in the KSEG0 and KSEG1 regions.

  tools/pic32mx/mkpichex:
  ----------------------

    There is a simple tool in the NuttX tools/pic32mx directory that can be
    used to solve both issues with the nuttx.hex file.  But, first, you must
    build the tool:

      cd tools/pic32mx
      make

    Now you will have an excecutable file call mkpichex (or mkpichex.exe on
    Cygwin).  This program will take the nutt.hex file as an input, it will
    convert all of the KSEG0 and KSEG1 addresses to physical address, and
    it will write the modified file, replacing the original nuttx.hex.

    To use this file, you need to do the following things:

      . ./setenv.sh    # Source setenv.sh.  Among other this, this script
                       # will add the NuttX tools/pic32mx directory to your
                       # PATH variable
      make             # Build nuttx and nuttx.hex
      mkpichex $PWD    # Convert addresses in nuttx.hex.  $PWD is the path
                       # to the top-level build directory.  It is the only
                       # required input to mkpichex.

LED Usage
=========

  The Mirtoo module has 2 user LEDs labeled LED0 and LED1 in the schematics:

    ---  ----- --------------------------------------------------------------
    PIN  Board Notes
    ---  ----- --------------------------------------------------------------
    RC8  LED0  Grounded, high value illuminates
    RC9  LED1  Grounded, high value illuminates

  The Dimitech DTX1-4000L EV-kit1 supports 3 more LEDs, but there are not
  controllable from software.

  If CONFIG_ARCH_LEDS is defined, then NuttX will control these LEDs as
  follows:
                                 ON        OFF
    ------------------------- ---- ---- ---- ----
                              LED0 LED1 LED0 LED1
    ------------------------- ---- ---- ---- ----
    LED_STARTED            0  OFF  OFF  ---  ---
    LED_HEAPALLOCATE       1  ON   OFF  ---  ---
    LED_IRQSENABLED        2  OFF  ON   ---  ---
    LED_STACKCREATED       3  ON   ON   ---  ---
    LED_INIRQ              4  ON   N/C  OFF  N/C
    LED_SIGNAL             4  ON   N/C  OFF  N/C
    LED_ASSERTION          4  ON   N/C  OFF  N/C
    LED_PANIC              4  ON   N/C  OFF  N/C

UART Usage
==========

  When mounted on the DTX1-4000L EV-kit1 board, serial output is avaiable through
  an FT230X device via the FUNC0 and FUNC1 module outputs.  If CONFIG_PIC32MX_UART2
  is enabled, the src/up_boot will configure the UART2 pins as follows:

    ---------- ------ ----- ------ -------------------------
       BOARD   MODULE  PIN  SIGNAL NOTES
    ---------- ------ ----- ------ -------------------------
    FT230X RXD  FUNC0 RPB11  U2RX  UART2 RX (Also PGEC2)
    FT230X TXD  FUNC1 RPB10  U2TX  UART2 TX (Also PGED2)

  However, since the FUNC0/1 pins are shared with the PGEC/D2, they cannot be used
  for UART2 if you are also debugging with the ICD3.  In that case, you may need
  to switch to UART1.

  If CONFIG_PIC32MX_UART1 is enabled, the src/up_boot will configure the UART
  pins as follows.  This will support communictions (via an external RS-232
  driver) through X3 pins 4 and 5:

    ---------- ------ ----- ------ -------------------------
       BOARD   MODULE  PIN  SIGNAL NOTES
    ---------- ------ ----- ------ -------------------------
    X3, pin 4   FUNC4 RPBC5  U1TX  UART1 TX
    X3, pin 5   FUNC5 RPBC6  U1RX  UART1 RX

  If you are not using MPLAB to debug, you may also want to change Make.defs
  to use the release.ld linker script instead of the debug.ld link script.  This
  change will give you a little more memory by re-using the boot FLASH and SRAM
  that would otherwise be reserved for MPLAB.

Analog Input
============

  The Mirtoo features a PGA117 amplifier/multipexer that can be configured to
  bring any analog signal from PORT0,.. PORT7 to pin 19 of the PIC32MX:

  --- ------------------------------------------------ ----------------------------
  PIN PIC32 SIGNAL(s)                                  BOARD SIGNAL/USAGE
  --- ------------------------------------------------ ----------------------------
  19  PGED3/VREF+/CVREF+/AN0/C3INC/RPA0/CTED1/PMD7/RA0 AIN PGA117 Vout
  --- ------------------------------------------------ ----------------------------

  The PGA117 driver can be enabled by setting the following the nsh
  configuration:

    CONFIG_ADC=y         : Enable support for analog input devices
    CONFIG_PIC32MX_ADC=y : Enable support the PIC32 ADC driver
    CONFIG_SPI_OWNBUS=n  : The PGA117 is *not* the only device on the bus
    CONFIG_ADC_PGA11X=y  : Enable support for the PGA117

  When CONFIG_PIC32MX_ADC=y is defined, the Mirtoo boot up logic will
  automatically configure pin 18 (AN0) as an analog input (see configs/mirtoo/src/up_adc.c).
  To intialize and use the PGA117, you to add logic something like the
  following in your application code:

  #include <nuttx/spi/spi.h>
  #include <nuttx/analog/pga11x.h>

  FAR struct spi_dev_s *spi;
  PGA11X_HANDLE handle;

  /* Get the SPI port */

  spi = up_spiinitialize(2);
  if (!spi)
    {
      dbg("ERROR: Failed to initialize SPI port 2\n");
      return -ENODEV;
    }

  /* Now bind the SPI interface to the PGA117 driver */

  handle = pga11x_initialize(spi);
  if (!handle)
    {
      dbg("ERROR: Failed to bind SPI port 2 to the PGA117 driver\n");
      return -ENODEV;
    }

  After that initialization is set, then one of PORT0-7 can be select as
  an analog input to AN0 like:

  struct pga11x_settings_s settings;
  int ret;

  settings.channel = PGA11X_CHAN_CH2;
  settings.gain    = PGA11X_GAIN_2;

  ret = pga11x_select(handle, &settings);
  if (ret < 0)
    {
      dbg("ERROR: Failed to select channel 2, gain 2\n");
      return -EIO;
    }

  The above logic may belong in configs/mirtoo/src/up_adc.c?

  There is still one missing piece to complete the analog support on the
  Mirtoo.  This is the ADC driver that collects analog data and provides
  and ADC driver that can be used with standard open, close, read, and write
  interfaces.  To complete this driver, the following is needed:

  (1) arch/mips/src/pic32mx/pic32mx-adc.c.  The ADC driver that implements
      the ADC interfaces defined in include/nuttx/analog/adc.h and must
      be built when CONFIG_PIC32MX_ADC is defined.

  (2) configs/mirtoo/up_adc.c.  Add Mirtoo logic that initializes and
      registers the ADC driver.

  A complete ADC driver will be a considerable amount of work to support
  all of the ADC features (such as timer driven sampling).  If all you want
  to do is a simple analog conversion, then in lieu of a real ADC driver,
  you can use simple in-line logic such as you can see in the PIC32MX7 MMB
  touchscreen driver at configs/pic32mx7mmb/src/up_touchscreen.c

PIC32MX Configuration Options
=============================

  General Architecture Settings:

    CONFIG_ARCH - Identifies the arch/ subdirectory.  This should
     be set to:

       CONFIG_ARCH=mips

    CONFIG_ARCH_family - For use in C code:

       CONFIG_ARCH_MIPS=y

    CONFIG_ARCH_architecture - For use in C code:

       CONFIG_ARCH_MIPS32=y

    CONFIG_ARCH_CHIP - Identifies the arch/*/chip subdirectory

       CONFIG_ARCH_CHIP=pic32mx

    CONFIG_ARCH_CHIP_name - For use in C code to identify the exact
       chip:

       CONFIG_ARCH_CHIP_PIC32MX250F128D=y

    CONFIG_ARCH_BOARD - Identifies the configs subdirectory and
       hence, the board that supports the particular chip or SoC.

       CONFIG_ARCH_BOARD=mirtoo

    CONFIG_ARCH_BOARD_name - For use in C code

       CONFIG_ARCH_BOARD_MIRTOO=y

    CONFIG_ARCH_LOOPSPERMSEC - Must be calibrated for correct operation
       of delay loops

    CONFIG_ENDIAN_BIG - define if big endian (default is little
       endian)

    CONFIG_RAM_SIZE - Describes the installed DRAM (CPU SRAM in this case):

       CONFIG_RAM_SIZE=(32*1024) (32Kb)

       There is an additional 32Kb of SRAM in AHB SRAM banks 0 and 1.

    CONFIG_RAM_START - The start address of installed DRAM

       CONFIG_RAM_START=0xa0000000

    CONFIG_ARCH_IRQPRIO - The PIC32MXx supports interrupt prioritization

       CONFIG_ARCH_IRQPRIO=y

    CONFIG_ARCH_LEDS - Use LEDs to show state. Unique to boards that
       have LEDs

    CONFIG_ARCH_INTERRUPTSTACK - This architecture supports an interrupt
       stack. If defined, this symbol is the size of the interrupt
       stack in bytes.  If not defined, the user task stacks will be
       used during interrupt handling.

    CONFIG_ARCH_STACKDUMP - Do stack dumps after assertions

    CONFIG_ARCH_LEDS -  Use LEDs to show state. Unique to board architecture.

    CONFIG_ARCH_CALIBRATION - Enables some build in instrumentation that
       cause a 100 second delay during boot-up.  This 100 second delay
       serves no purpose other than it allows you to calibratre
       CONFIG_ARCH_LOOPSPERMSEC.  You simply use a stop watch to measure
       the 100 second delay then adjust CONFIG_ARCH_LOOPSPERMSEC until
       the delay actually is 100 seconds.

    PIC32MX Configuration

      CONFIG_PIC32MX_MVEC - Select muli- vs. single-vectored interrupts

    Individual subsystems can be enabled:

       CONFIG_PIC32MX_WDT            - Watchdog timer
       CONFIG_PIC32MX_T2             - Timer 2 (Timer 1 is the system time and always enabled)
       CONFIG_PIC32MX_T3             - Timer 3
       CONFIG_PIC32MX_T4             - Timer 4
       CONFIG_PIC32MX_T5             - Timer 5
       CONFIG_PIC32MX_IC1            - Input Capture 1
       CONFIG_PIC32MX_IC2            - Input Capture 2
       CONFIG_PIC32MX_IC3            - Input Capture 3
       CONFIG_PIC32MX_IC4            - Input Capture 4
       CONFIG_PIC32MX_IC5            - Input Capture 5
       CONFIG_PIC32MX_OC1            - Output Compare 1
       CONFIG_PIC32MX_OC2            - Output Compare 2
       CONFIG_PIC32MX_OC3            - Output Compare 3
       CONFIG_PIC32MX_OC4            - Output Compare 4
       CONFIG_PIC32MX_OC5            - Output Compare 5
       CONFIG_PIC32MX_I2C1           - I2C 1
       CONFIG_PIC32MX_I2C2           - I2C 2
       CONFIG_PIC32MX_SPI1           - SPI 1
       CONFIG_PIC32MX_SPI2           - SPI 2
       CONFIG_PIC32MX_UART1          - UART 1
       CONFIG_PIC32MX_UART2          - UART 2
       CONFIG_PIC32MX_ADC            - ADC 1
       CONFIG_PIC32MX_PMP            - Parallel Master Port
       CONFIG_PIC32MX_CM1            - Comparator 1
       CONFIG_PIC32MX_CM2            - Comparator 2
       CONFIG_PIC32MX_CM3            - Comparator 3
       CONFIG_PIC32MX_RTCC           - Real-Time Clock and Calendar
       CONFIG_PIC32MX_DMA            - DMA
       CONFIG_PIC32MX_FLASH          - FLASH
       CONFIG_PIC32MX_USBDEV         - USB device
       CONFIG_PIC32MX_USBHOST        - USB host
       CONFIG_PIC32MX_CTMU           - CTMU

    PIC32MX Configuration Settings
    DEVCFG0:
      CONFIG_PIC32MX_DEBUGGER - Background Debugger Enable. Default 3 (disabled). The
        value 2 enables.
      CONFIG_PIC32MX_ICESEL - In-Circuit Emulator/Debugger Communication Channel Select
        Default 1 (PG2)
      CONFIG_PIC32MX_PROGFLASHWP  - Program FLASH write protect.  Default 0xff (disabled)
      CONFIG_PIC32MX_BOOTFLASHWP - Default 1 (disabled)
      CONFIG_PIC32MX_CODEWP - Default 1 (disabled)
    DEVCFG1: (All settings determined by selections in board.h)
    DEVCFG2: (All settings determined by selections in board.h)
    DEVCFG3:
      CONFIG_PIC32MX_USBIDO - USB USBID Selection.  Default 1 if USB enabled
        (USBID pin is controlled by the USB module), but 0 (GPIO) otherwise.
      CONFIG_PIC32MX_VBUSIO - USB VBUSON Selection (Default 1 if USB enabled
        (VBUSON pin is controlled by the USB module, but 0 (GPIO) otherwise.
      CONFIG_PIC32MX_WDENABLE - Enabled watchdog on power up.  Default 0 (watchdog
        can be enabled later by software).

    The priority of interrupts may be specified.  The value ranage of
    priority is 4-31. The default (16) will be used if these any of these
    are undefined.

       CONFIG_PIC32MX_CTPRIO         - Core Timer Interrupt
       CONFIG_PIC32MX_CS0PRIO        - Core Software Interrupt 0
       CONFIG_PIC32MX_CS1PRIO        - Core Software Interrupt 1
       CONFIG_PIC32MX_INT0PRIO       - External Interrupt 0
       CONFIG_PIC32MX_INT1PRIO       - External Interrupt 1
       CONFIG_PIC32MX_INT2PRIO       - External Interrupt 2
       CONFIG_PIC32MX_INT3PRIO       - External Interrupt 3
       CONFIG_PIC32MX_INT4PRIO       - External Interrupt 4
       CONFIG_PIC32MX_FSCMPRIO       - Fail-Safe Clock Monitor
       CONFIG_PIC32MX_T1PRIO         - Timer 1 (System timer) priority
       CONFIG_PIC32MX_T2PRIO         - Timer 2 priority
       CONFIG_PIC32MX_T3PRIO         - Timer 3 priority
       CONFIG_PIC32MX_T4PRIO         - Timer 4 priority
       CONFIG_PIC32MX_T5PRIO         - Timer 5 priority
       CONFIG_PIC32MX_IC1PRIO        - Input Capture 1
       CONFIG_PIC32MX_IC2PRIO        - Input Capture 2
       CONFIG_PIC32MX_IC3PRIO        - Input Capture 3
       CONFIG_PIC32MX_IC4PRIO        - Input Capture 4
       CONFIG_PIC32MX_IC5PRIO        - Input Capture 5
       CONFIG_PIC32MX_OC1PRIO        - Output Compare 1
       CONFIG_PIC32MX_OC2PRIO        - Output Compare 2
       CONFIG_PIC32MX_OC3PRIO        - Output Compare 3
       CONFIG_PIC32MX_OC4PRIO        - Output Compare 4
       CONFIG_PIC32MX_OC5PRIO        - Output Compare 5
       CONFIG_PIC32MX_I2C1PRIO       - I2C 1
       CONFIG_PIC32MX_I2C2PRIO       - I2C 2
       CONFIG_PIC32MX_SPI1PRIO       - SPI 1
       CONFIG_PIC32MX_SPI2PRIO       - SPI 2
       CONFIG_PIC32MX_UART1PRIO      - UART 1
       CONFIG_PIC32MX_UART2PRIO      - UART 2
       CONFIG_PIC32MX_CN             - Input Change Interrupt
       CONFIG_PIC32MX_ADCPRIO        - ADC1 Convert Done
       CONFIG_PIC32MX_PMPPRIO        - Parallel Master Port
       CONFIG_PIC32MX_CM1PRIO        - Comparator 1
       CONFIG_PIC32MX_CM2PRIO        - Comparator 2
       CONFIG_PIC32MX_FSCMPRIO       - Fail-Safe Clock Monitor
       CONFIG_PIC32MX_RTCCPRIO       - Real-Time Clock and Calendar
       CONFIG_PIC32MX_DMA0PRIO       - DMA Channel 0
       CONFIG_PIC32MX_DMA1PRIO       - DMA Channel 1
       CONFIG_PIC32MX_DMA2PRIO       - DMA Channel 2
       CONFIG_PIC32MX_DMA3PRIO       - DMA Channel 3
       CONFIG_PIC32MX_FCEPRIO        - Flash Control Event
       CONFIG_PIC32MX_USBPRIO        - USB

  PIC32MXx specific device driver settings

    CONFIG_UARTn_SERIAL_CONSOLE - selects the UARTn for the
       console and ttys0 (default is the UART0).
    CONFIG_UARTn_RXBUFSIZE - Characters are buffered as received.
       This specific the size of the receive buffer
    CONFIG_UARTn_TXBUFSIZE - Characters are buffered before
       being sent.  This specific the size of the transmit buffer
    CONFIG_UARTn_BAUD - The configure BAUD of the UART.  Must be
    CONFIG_UARTn_BITS - The number of bits.  Must be either 7 or 8.
    CONFIG_UARTn_PARTIY - 0=no parity, 1=odd parity, 2=even parity
    CONFIG_UARTn_2STOP - Two stop bits

  PIC32MXx USB Device Configuration

  PIC32MXx USB Host Configuration (the PIC32MX does not support USB Host)

Configurations
==============

Each PIC32MX configuration is maintained in a sub-directory and can be
selected as follow:

    cd tools
    ./configure.sh mirtoo/<subdir>
    cd -
    . ./setenv.sh

Where <subdir> is one of the following:

  ostest:
  =======
    This configuration directory, performs a simple OS test using
    apps/examples/ostest.  This configuration use UART1 which is
    available on FUNC 4 and 5 on connector X3:

      CONFIG_PIC32MX_UART1=y           : UART1 for serial console
      CONFIG_UART1_SERIAL_CONSOLE=n

    If you are not using MPLAB to debug, you may switch to UART2
    by editting the .config file after configuration to disable UART1
    and select UART2.  You should also change Make.defs to use the
    release.ld linker script instead of the debug.ld link script.

    This configuration also uses the Microchip C32 toolchain under
    windows by default:

      CONFIG_PIC32MX_MICROCHIPW_LITE=y : Lite version of windows toolchain

    To switch to the Linux C32 toolchain you will have to change (1) the
    toolchain selection in .config (after configuration) and (2) the
    path to the toolchain in setenv.sh.  See notes above with regard to
    the XC32 toolchain.

  nsh:
  ====
    This configuration directory holds configuration files tht can
    be used to support the NuttShell (NSH).  This configuration use
    UART1 which is available on FUNC 4 and 5 on connector X3:

      CONFIG_PIC32MX_UART1=y           : UART1 for serial console
      CONFIG_UART1_SERIAL_CONSOLE=n

    UART2
    -----
    If you are not using MPLAB to debug, you may switch to UART2
    by following the instructions above for the ostest configuration.

    This configuration also uses the Microchip C32 toolchain under
    windows by default:

      CONFIG_PIC32MX_MICROCHIPW_LITE=y : Lite version of windows toolchain

    To switch to the Linux C32 toolchain you will have to change (1) the
    toolchain selection in .config (after configuration) and (2) the
    path to the toolchain in setenv.sh.  See notes above with regard to
    the XC32 toolchain.

    PGA117 Support:
    --------------
    The Mirtoo's PGA117 amplifier/multipexer is not used by this configuration
    but can be enabled by setting:

       CONFIG_ADC=y         : Enable support for analog input devices
       CONFIG_SPI_OWNBUS=y  : If the PGA117 is the only device on the bus
       CONFIG_ADC_PGA11X=y  : Enable support for the PGA117

  nxffs:
  ======
    This is a configuration very similar to the nsh configuration.  This
    configure also provides the NuttShell (NSH).  And this configuration use
    UART1 which is available on FUNC 4 and 5 on connector X3 (as described
    for the nsh configuration).  This configuration differs from the nsh
    configuration in the following ways:

    1) It uses the Pinguino toolchain be default (this is easily changed,
       see above).

       CONFIG_PIC32MX_PINGUINOW=y

    2) SPI2 is enabled and support is included for the NXFFS file system
       on the 32Mbit SST25 device on the Mirtoo board.  NXFFS is the NuttX
       wear-leveling file system.

       CONFIG_PIC32MX_SPI2=y
       CONFIG_MTD_SST25=y
       CONFIG_SST25_SECTOR512=y
       CONFIG_DISABLE_MOUNTPOINT=n
       CONFIG_FS_NXFFS=y
       CONFIG_NSH_ARCHINIT=y

    3) Many operating system features are suppressed to produce a smaller
       footprint.

       CONFIG_SCHED_WAITPID=n
       CONFIG_DISABLE_POSIX_TIMERS=y
       CONFIG_DISABLE_PTHREAD=y
       CONFIG_DISABLE_MQUEUE=y
       CONFIG_DISABLE_MQUEUE=y

    4) Many NSH commands are suppressed, also for a smaller FLASH footprint

       CONFIG_NSH_DISABLESCRIPT=y
       CONFIG_NSH_DISABLEBG=y

       CONFIG_NSH_DISABLE_DD=y
       CONFIG_NSH_DISABLE_EXEC=y
       CONFIG_NSH_DISABLE_EXIT=y
       CONFIG_NSH_DISABLE_GET=y
       CONFIG_NSH_DISABLE_IFCONFIG=y
       CONFIG_NSH_DISABLE_KILL=y
       CONFIG_NSH_DISABLE_MKFATFS=y
       CONFIG_NSH_DISABLE_MKFIFO=y
       CONFIG_NSH_DISABLE_MKRD=y
       CONFIG_NSH_DISABLE_NFSMOUNT=y
       CONFIG_NSH_DISABLE_PING=y
       CONFIG_NSH_DISABLE_PUT=y
       CONFIG_NSH_DISABLE_SH=y
       CONFIG_NSH_DISABLE_TEST=y
       CONFIG_NSH_DISABLE_WGET=y

    When the system boots, you should have the NXFFS file system mounted
    at /mnt/sst25.

    NOTES:  (1) It takes many seconds to boot the sytem using the NXFFS
    file system because the entire FLASH must be verified on power up
    (and longer the first time that NXFFS comes up and has to format the
    entire FLASH). (2) FAT does not have these delays and this configuration
    can be modified to use the (larger) FAT file system as described below.
    But you will, or course, lose the wear-leveling feature if FAT is used.

    fat:
    ----
    There is no FAT configuration, but the nxffx configuration can be used
    to support the FAT FS if the following changes are made to the NuttX
    configuration file:

      CONFIG_FS_NXFFS=n
      CONFIG_FS_FAT=y
      CONFIG_NSH_DISABLE_MKFATFS=n

    In this configuration, the FAT file system will not be automatically
    monounted.  When NuttX boots to the NSH prompt, you will find the
    SST5 block driver at /dev/mtdblock0.  This can be formatted with a
    FAT file system and mounted with these commands:

      nsh> mkfatfs /dev/mtdblock0
      nsh> mount -t vfat /dev/mtdblock0 /mnt/sst25

    PGA117 Support:
    ---------------
    The Mirtoo's PGA117 amplifier/multipexer is not used by this configuration
    but can be enabled by setting:

      CONFIG_ADC=y         : Enable support for anlog input devices
      CONFIG_SPI_OWNBUS=n  : The PGA117 is *not* the only device on the bus
      CONFIG_ADC_PGA11X=y  : Enable support for the PGA117

