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[stm32][sys_time][ppm] run cortex systick timer at full AHB freq again, ppm at AHB/9

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This commit is contained in:
Felix Ruess
2013-02-26 19:42:19 +01:00
parent 924956fb76
commit 523e2dabea
4 changed files with 13 additions and 17 deletions
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sw/airborne/arch/lpc21/subsystems/radio_control/ppm_arch.h
+1 -1
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@@ -35,7 +35,7 @@
*
*/
#define RC_PPM_TICKS_OF_USEC(_v) cpu_ticks_of_usec((_v))
#define RC_PPM_SIGNED_TICKS_OF_USEC(_v) (int32_t)((_v) * sys_time.cpu_ticks_per_sec * 1e-6)
#define RC_PPM_SIGNED_TICKS_OF_USEC(_v) ((_v) * sys_time.cpu_ticks_per_sec * 1e-6)
#define USEC_OF_RC_PPM_TICKS(_v) usec_of_cpu_ticks((_v))
#define PPM_NB_CHANNEL RADIO_CONTROL_NB_CHANNEL
sw/airborne/arch/stm32/mcu_periph/sys_time_arch.c
+6 -8
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@@ -37,12 +37,11 @@
/** Initialize SysTick.
* Generate SysTick interrupt every sys_time.resolution_cpu_ticks
* The timer interrupt is activated on the transition from 1 to 0,
* therefore it activates every n+1 clock ticks.
*/
void sys_time_arch_init( void ) {
/* 72MHz / 8 => 9000000 counts per second */
sys_time.cpu_ticks_per_sec = AHB_CLK / 8;
/* run cortex systick timer with 72MHz */
systick_set_clocksource(STK_CTRL_CLKSOURCE_AHB);
sys_time.cpu_ticks_per_sec = AHB_CLK;
/* cpu ticks per desired sys_time timer step */
sys_time.resolution_cpu_ticks = (uint32_t)(sys_time.resolution_sec * sys_time.cpu_ticks_per_sec + 0.5);
@@ -51,10 +50,9 @@ void sys_time_arch_init( void ) {
sys_time.resolution_sec = (float)sys_time.resolution_cpu_ticks / sys_time.cpu_ticks_per_sec;
sys_time.ticks_per_sec = (uint32_t)(sys_time.cpu_ticks_per_sec / sys_time.resolution_cpu_ticks + 0.5);
/* set clock for cortex systick to AHB_CLK / 8 */
systick_set_clocksource(STK_CTRL_CLKSOURCE_AHB_DIV8);
/* 8999 would be one interrupt every 1ms */
/* The timer interrupt is activated on the transition from 1 to 0,
* therefore it activates every n+1 clock ticks.
*/
systick_set_reload(sys_time.resolution_cpu_ticks-1);
systick_interrupt_enable();
sw/airborne/arch/stm32/subsystems/radio_control/ppm_arch.c
+2 -2
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@@ -97,8 +97,8 @@ void ppm_arch_init ( void ) {
timer_set_mode(PPM_TIMER, TIM_CR1_CKD_CK_INT,
TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
timer_set_period(PPM_TIMER, 0xFFFF);
/* run ppm timer at cpu freq / 8 */
timer_set_prescaler(PPM_TIMER, 7);
/* run ppm timer at cpu freq / 9 = 8MHz */
timer_set_prescaler(PPM_TIMER, 8);
/* TIM configuration: Input Capture mode ---------------------
The Rising edge is used as active edge,
sw/airborne/arch/stm32/subsystems/radio_control/ppm_arch.h
+4 -6
View File
@@ -33,13 +33,11 @@
#include "mcu_periph/sys_time.h"
/**
* While the ppm counter is currently running at the same speed as
* the systick counter, there is no reason for this to be true.
* Let's add a pair of macros to make it possible for them to be different.
* The ppm counter is running at cpu freq / 9
*/
#define RC_PPM_TICKS_OF_USEC(_v) cpu_ticks_of_usec((_v))
#define RC_PPM_SIGNED_TICKS_OF_USEC(_v) (int32_t)((_v) * sys_time.cpu_ticks_per_sec * 1e-6)
#define USEC_OF_RC_PPM_TICKS(_v) usec_of_cpu_ticks((_v))
#define RC_PPM_TICKS_OF_USEC(_v) ((_v) * (AHB_CLK / 9000000))
#define RC_PPM_SIGNED_TICKS_OF_USEC(_v) ((_v) * (AHB_CLK / 9000000))
#define USEC_OF_RC_PPM_TICKS(_v) ((_v) / (AHB_CLK / 9000000))
#define PPM_NB_CHANNEL RADIO_CONTROL_NB_CHANNEL