Diff: Device/FastPWM_KL25Z.cpp

Revision:

4:a7b9f778c4b4

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Device/FastPWM_KL25Z.cpp	Tue Aug 13 16:54:06 2013 +0000
@@ -0,0 +1,56 @@
+#ifdef TARGET_KL25Z
+
+#include "FastPWM.h"
+
+volatile uint32_t *TPM_SC;
+
+void FastPWM::initFastPWM( void ) {
+    bits = 16;
+    
+    //Yes this is ugly, yes I should feel bad about it
+    TPM_SC = _pwm.MOD - 2;
+}
+
+void FastPWM::pulsewidth_ticks( uint32_t ticks ) {
+    *(_pwm.CnV) = ticks;
+    *_pwm.CNT = 0;  //Not yet sure why this is needed!
+}
+
+void FastPWM::period_ticks( uint32_t ticks ) {
+    *(_pwm.MOD) = ticks;
+    *_pwm.CNT = 0;
+}
+
+uint32_t FastPWM::getPeriod( void ) {
+    return *(_pwm.MOD);
+}
+
+uint32_t FastPWM::setPrescaler(uint32_t reqScale) {
+    const char prescalers[] = {1, 2, 4, 8, 16, 32, 64, 128};
+    
+    //If prescaler is 0, return current one
+    if (reqScale == 0)
+        return (prescalers[(*TPM_SC) & 0x07]);
+    
+    uint32_t retval = 0;
+    char bin;
+    
+    for (bin = 0; bin<8; bin++) {
+        retval = prescalers[bin];
+        if (retval >= reqScale)
+            break;
+    }
+    
+    //Clear lower 5 bits, write new value:
+    char clockbits = *TPM_SC & (3<<3);
+    
+    //For some reason clearing them takes some effort
+    while ((*TPM_SC & 0x1F) != 0)
+        *TPM_SC &= ~0x1F;
+        
+    
+    *TPM_SC |= bin + clockbits;
+    
+    return retval;   
+}
+#endif
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