docs/guides/lwl: move lwl's README.txt to lwl.rst

This PR moves the lwl's READEME.txt file to Documentation/guides/lwl.rst

Signed-off-by: Luchian Mihai <luchiann.mihai@gmail.com>

Documentation/guides/index.rst

@@ -61,4 +61,5 @@ Guides
   rust.rst
   optee.rst
   qemu_tips.rst
+  lwl.rst
 

Documentation/guides/lwl.rst

@@ -1,15 +1,16 @@
+=============================
 Console over Lightweight Link
 =============================
 
 LWL is a Lightweight bidirectional communication between target and debug host
 without any need for additional hardware.
-
+ 
 It works with openOCD and other debuggers that are capable of reading and
 writing memory while the target is running...it should run with JLink
 for example, if you've got the SDK and modify this file accordingly.
 
-Principle of operation is simple; An 'upword' of 32 bits communicates
-from the target to the host, a 'downword' of the same size runs in the
+Principle of operation is simple; An `'upword'` of 32 bits communicates
+from the target to the host, a `'downword'` of the same size runs in the
 opposite direction. These two words can be in any memory that is
 read/write access for both the target and the debug host. A simple ping
 pong handshake protocol over these words allows up/down link communication.
@@ -25,7 +26,8 @@ upwordaddr if you want to work with fixed locations.
 Bit configuration
 -----------------
 
-Downword (Host to target);
+Downword (Host to target)
+^^^^^^^^^^^^^^^^^^^^^^^^^
 
 A D U VV XXX O2 O1 O0
 
@@ -38,7 +40,8 @@ O2  23-16 8 - Octet 2
 O1  15-08 8 - Octet 1
 O0  07-00 8 - Octet 0
 
-Upword (Target to Host);
+Upword (Target to Host)
+^^^^^^^^^^^^^^^^^^^^^^^
 
 A   31    1 - Service Active (Set by device)
 D   30    1 - Downsense ack (Toggled to acknowledge receipt of downlink data)
@@ -61,55 +64,55 @@ In the first terminal execute the openocd command to connect to the board.
 Assuming that you already flashed to firmware (nuttx.bin) with the LWL
 console support. For stm32f4discovery board I use this command:
 
-------------------------------------------
-$ sudo openocd -f board/stm32f4discovery.cfg
-Open On-Chip Debugger  v0.10.0-esp32-20200526-6-g4c41a632 (2020-06-23-10:12)
-Licensed under GNU GPL v2
-For bug reports, read
-	http://openocd.org/doc/doxygen/bugs.html
-Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
-srst_only separate srst_nogate srst_open_drain connect_deassert_srst
+.. code-block:: console
 
-Info : Listening on port 6666 for tcl connections
-Info : Listening on port 4444 for telnet connections
-Info : clock speed 2000 kHz
-Info : STLINK V2J17S0 (API v2) VID:PID 0483:3748
-Info : Target voltage: 3.216252
-Info : stm32f4x.cpu: hardware has 6 breakpoints, 4 watchpoints
-Info : Listening on port 3333 for gdb connections
-Info : accepting 'tcl' connection on tcp/6666
-invalid command name "ocd_mdw"
-0x20000000: 000000ff
+  $ sudo openocd -f board/stm32f4discovery.cfg
+  Open On-Chip Debugger  v0.10.0-esp32-20200526-6-g4c41a632 (2020-06-23-10:12)
+  Licensed under GNU GPL v2
+  For bug reports, read
+  	http://openocd.org/doc/doxygen/bugs.html
+  Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
+  srst_only separate srst_nogate srst_open_drain connect_deassert_srst
+  
+  Info : Listening on port 6666 for tcl connections
+  Info : Listening on port 4444 for telnet connections
+  Info : clock speed 2000 kHz
+  Info : STLINK V2J17S0 (API v2) VID:PID 0483:3748
+  Info : Target voltage: 3.216252
+  Info : stm32f4x.cpu: hardware has 6 breakpoints, 4 watchpoints
+  Info : Listening on port 3333 for gdb connections
+  Info : accepting 'tcl' connection on tcp/6666
+  invalid command name "ocd_mdw"
+  0x20000000: 000000ff
 
-0x20000000: 000000ff
+  0x20000000: 000000ff
+  
+  0x20000004: 7216a318
+  
+  0x2000000c: 994b5b1b
+  
+  0x2000000c: 994b5b1b
+  
+  0x2000000c: 994b5b1b
 
-0x20000004: 7216a318
-
-0x2000000c: 994b5b1b
-
-0x2000000c: 994b5b1b
-
-0x2000000c: 994b5b1b
-...
-
-The "0x2000000c:..." will repeat all the time.
+  ...
 
 Now in another terminal execute:
 
-------------------------------------------
-$ ./ocdconsole.py
-==Link Activated
+.. code-block:: console
 
-nsh>
-nsh> help
-help usage:  help [-v] [<cmd>]
+  $ ./ocdconsole.py
+  ==Link Activated
+  
+  nsh>
+  nsh> help
+  help usage:  help [-v] [<cmd>]
+  
+   ?        echo     exit     hexdump  ls       mh       sleep    xd
+   cat      exec     help     kill     mb       mw       usleep
+  nsh>
 
- ?        echo     exit     hexdump  ls       mh       sleep    xd
- cat      exec     help     kill     mb       mw       usleep
-nsh>
-------------------------------------------
-
-This code is designed to be 'hardy' and will survive a shutdown and
+This code is designed to be `'hardy'` and will survive a shutdown and
 restart of the openocd process. When your target application
 changes then the location of the upword and downword may change,
 so they are re-searched for again. To speed up the start process
@@ -124,4 +127,4 @@ better performance it could use interrupts to detect when the memory
 position was modified to read the data.
 
 It also will avoid using busy waiting inside the driver, look at
-nuttx/arch/arm/src/common/arm_lwl_console.c for more information.
+``nuttx/arch/arm/src/common/arm_lwl_console.c`` for more information.