FASTPWM

Dependents:   OV7670_make

Revision:
13:cdefd9d75b64
Child:
17:8378bc456f0d
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Device/FastPWM_STM_TIM.cpp	Sun Jul 20 19:49:43 2014 +0000
@@ -0,0 +1,42 @@
+//This should (hopefully) work on all STM targets which use TIM timers for PWM
+
+#ifdef TARGET_STM
+
+#include "FastPWM.h"
+
+#define PWM_CHANNEL     (**(__IO uint32_t**)fast_obj)
+#define PWM_TIMER       ((TIM_TypeDef*)_pwm.pwm)
+
+extern __IO uint32_t* getChannel(TIM_TypeDef* pwm, PinName pin);
+
+void FastPWM::initFastPWM( void ) {
+    fast_obj = new (__IO uint32_t*);
+    *(__IO uint32_t**)fast_obj = getChannel(PWM_TIMER, _pwm.pin);
+    bits = 16;
+}
+
+void FastPWM::pulsewidth_ticks( uint32_t ticks ) {
+    PWM_CHANNEL = ticks;    
+}
+
+void FastPWM::period_ticks( uint32_t ticks ) {
+    PWM_TIMER->ARR = ticks - 1;
+}
+
+uint32_t FastPWM::getPeriod( void ) {
+    return PWM_TIMER->ARR + 1;
+}
+
+uint32_t FastPWM::setPrescaler(uint32_t reqScale) {
+    if (reqScale == 0)
+        //Return prescaler
+        return PWM_TIMER->PSC + 1;
+    if (reqScale > (uint32_t)(1<<16))
+        reqScale = 1<<16;
+    //Else set prescaler, we have to substract one from reqScale since a 0 in PCVAL is prescaler of 1
+    PWM_TIMER->PSC = reqScale - 1;
+
+    return reqScale;
+}
+
+#endif
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