Revision 30:52e9205a8059, committed 2014-01-04

Comitter:

bikeNomad

Date:

Sat Jan 04 00:32:16 2014 +0000

Parent:

29:a76075c853ee

Child:

31:c9eee3a33826

Commit message:

used TPM0 to time guard time at end of DMA.

Changed in this revision

--- a/WS2811.cpp	Fri Jan 03 19:17:24 2014 +0000
+++ b/WS2811.cpp	Sat Jan 04 00:32:16 2014 +0000
@@ -28,7 +28,7 @@
 #define MONITOR_TPM0_PWM 0
 
 // define DEBUG_PIN to identify a pin in PORTD used for debug output
-// #define DEBUG_PIN 3 /* PTD3 debugOut */
+// #define DEBUG_PIN 4 /* PTD4 debugOut */
 
 #ifdef DEBUG_PIN
 #define DEBUG 1
@@ -49,10 +49,12 @@
 
 // 48 MHz clock, no prescaling.
 #define NSEC_TO_TICKS(nsec) ((nsec)*48/1000)
+#define USEC_TO_TICKS(usec) ((usec)*48)
 static const uint32_t CLK_NSEC = 1250;
 static const uint32_t tpm_period    = NSEC_TO_TICKS(CLK_NSEC);
 static const uint32_t tpm_p0_period = NSEC_TO_TICKS(250);
 static const uint32_t tpm_p1_period = NSEC_TO_TICKS(650);
+static const uint32_t guardtime_period = USEC_TO_TICKS(55);   // guardtime minimum 50 usec.
 
 enum DMA_MUX_SRC {
     DMA_MUX_SRC_TPM0_CH_0     = 24,
@@ -67,15 +69,12 @@
     N_DMA_CHANNELS
 };
 
-static volatile bool dma_done = true;
+volatile bool WS2811::dma_done = true;
 
 // class static
 bool WS2811::initialized = false;
 
 // class static
-Timer WS2811::guardtime;
-
-// class static
 uint32_t WS2811::enabledPins = 0;
 
 #define WORD_ALIGNED __attribute__ ((aligned(4)))
@@ -95,18 +94,10 @@
 } dmaData WORD_ALIGNED;
 
 // class static
-bool WS2811::is_dma_done()
-{
-    return dma_done;
-}
-
-// class static
 void WS2811::hw_init()
 {
     if (initialized) return;
 
-    guardtime.start();
-
     dma_data_init();
     clock_init();
     dma_init();
@@ -114,6 +105,9 @@
     tpm_init();
 
     initialized = true;
+
+    SET_DEBUG;
+    RESET_DEBUG;
 }
 
 // class static
@@ -192,6 +186,7 @@
     // t=tpm_p1_period: all outputs go low.
     DMAMUX0->CHCFG[DMA_CHAN_1_LOW] = DMAMUX_CHCFG_ENBL_MASK | DMAMUX_CHCFG_SOURCE(DMA_MUX_SRC_TPM0_CH_1);
 
+    NVIC_SetVector(DMA0_IRQn, (uint32_t)&DMA0_IRQHandler);
     NVIC_EnableIRQ(DMA0_IRQn);
 }
 
@@ -203,6 +198,7 @@
     // set up TPM0 for proper period (800 kHz = 1.25 usec ±600nsec)
     TPM_Type volatile *tpm = TPM0;
     tpm->SC = TPM_SC_DMA_MASK          // enable DMA
+              | TPM_SC_TOF_MASK        // reset TOF flag if set
               | TPM_SC_CMOD(0)         // disable clocks
               | TPM_SC_PS(0);          // 48MHz / 1 = 48MHz clock
     tpm->MOD = tpm_period - 1;         // 48MHz / 800kHz
@@ -211,13 +207,16 @@
     tpm->CONTROLS[0].CnSC = TPM_CnSC_MSB_MASK | TPM_CnSC_ELSB_MASK | TPM_CnSC_DMA_MASK;
     tpm->CONTROLS[1].CnSC = TPM_CnSC_MSB_MASK | TPM_CnSC_ELSB_MASK | TPM_CnSC_DMA_MASK;
 
-    // set TPM0 channel 0 for 0.35 usec (±150nsec) / 0.8 usec (±150nsec) (0 code)
+    // set TPM0 channel 0 for 0.35 usec (±150nsec) (0 code)
     // 1.25 usec * 1/3 = 417 nsec
     tpm->CONTROLS[0].CnV = tpm_p0_period;
 
-    // set TPM0 channel 1 for 0.7 usec (±150nsec) / 0.6 usec (±150nsec) (1 code)
+    // set TPM0 channel 1 for 0.7 usec (±150nsec) (1 code)
     // 1.25 usec * 2/3 = 833 nsec
     tpm->CONTROLS[1].CnV = tpm_p1_period;
+
+    NVIC_SetVector(TPM0_IRQn, (uint32_t)&TPM0_IRQHandler);
+    NVIC_EnableIRQ(TPM0_IRQn);
 }
 
 WS2811::WS2811(unsigned n, unsigned pinNumber)
@@ -225,12 +224,16 @@
     , pinMask(1U << pinNumber)
 {
     enabledPins |= pinMask;
+    initialized = false;
 }
 
 // class static
 void WS2811::startDMA()
 {
     hw_init();
+    
+    wait_for_dma_done();
+    dma_done = false;
 
     DMA_Type volatile * dma   = DMA0;
     TPM_Type volatile *tpm   = TPM0;
@@ -238,7 +241,12 @@
                       + sizeof(dmaData.dmaWords)
                       + sizeof(dmaData.trailing_zeros_1);
 
-    tpm->SC &= ~TPM_SC_CMOD_MASK; // disable internal clocking
+    tpm->SC = TPM_SC_DMA_MASK        // enable DMA
+              | TPM_SC_TOF_MASK  // reset TOF flag if set
+              | TPM_SC_CMOD(0)   // disable clocks
+              | TPM_SC_PS(0);    // 48MHz / 1 = 48MHz clock
+    tpm->MOD = tpm_period - 1;       // 48MHz / 800kHz
+
     tpm->CNT = tpm_p0_period - 2 ;
     tpm->STATUS = 0xFFFFFFFF;
 
@@ -269,16 +277,6 @@
       = dma->DMA[DMA_CHAN_START].DAR
         = (uint32_t)(void*)&IO_GPIO->PDOR;
 
-    // wait until done
-    while (!is_dma_done()) {
-        __WFI();
-    }
-
-    // ensure sufficient guard time
-    while (guardtime.read_us() < 50) {
-        __NOP();
-    }
-
     SET_DEBUG;
 
     dma->DMA[DMA_CHAN_0_LOW].DCR     = DMA_DCR_EINT_MASK // enable interrupt on end of transfer
@@ -304,7 +302,6 @@
                                        | DMA_DCR_SSIZE(0) // 32-bit source transfers
                                        | DMA_DCR_DSIZE(0);
 
-
     tpm->SC |= TPM_SC_CMOD(1);         // enable internal clocking
 }
 
@@ -361,26 +358,42 @@
 
 extern "C" void DMA0_IRQHandler()
 {
-    DMA_Type volatile * dma = DMA0;
-    TPM_Type volatile *tpm   = TPM0;
+    DMA_Type volatile *dma = DMA0;
+    TPM_Type volatile *tpm = TPM0;
 
-    uint32_t db = dma->DMA[DMA_CHAN_START].DSR_BCR;
-    if (db & DMA_DSR_BCR_DONE_MASK) {
-        dma->DMA[DMA_CHAN_START].DSR_BCR = DMA_DSR_BCR_DONE_MASK;  // clear/reset DMA status
-    }
+    uint32_t db;
 
     db = dma->DMA[DMA_CHAN_0_LOW].DSR_BCR;
     if (db & DMA_DSR_BCR_DONE_MASK) {
-        dma->DMA[DMA_CHAN_0_LOW].DSR_BCR = DMA_DSR_BCR_DONE_MASK;  // clear/reset DMA status
+        dma->DMA[DMA_CHAN_0_LOW].DSR_BCR = DMA_DSR_BCR_DONE_MASK; // clear/reset DMA status
     }
 
     db = dma->DMA[DMA_CHAN_1_LOW].DSR_BCR;
     if (db & DMA_DSR_BCR_DONE_MASK) {
         dma->DMA[DMA_CHAN_1_LOW].DSR_BCR = DMA_DSR_BCR_DONE_MASK; // clear/reset DMA status
-        dma_done                         = true;
-        tpm->SC &= ~TPM_SC_CMOD_MASK; // disable internal clocking
-        RESET_DEBUG;
-        WS2811::guardtime.reset();
+    }
+
+    db = dma->DMA[DMA_CHAN_START].DSR_BCR;
+    if (db & DMA_DSR_BCR_DONE_MASK) {
+        dma->DMA[DMA_CHAN_START].DSR_BCR = DMA_DSR_BCR_DONE_MASK; // clear/reset DMA status
     }
+
+    tpm->SC = TPM_SC_TOF_MASK;  // reset TOF flag; disable internal clocking
+
+    SET_DEBUG;
+
+    // set TPM0 to interrrupt after guardtime
+    tpm->MOD = guardtime_period - 1; // 48MHz * 55 usec
+    tpm->CNT = 0;
+    tpm->SC  = TPM_SC_PS(0)        // 48MHz / 1 = 48MHz clock
+               | TPM_SC_TOIE_MASK  // enable interrupts
+               | TPM_SC_CMOD(1);   // and internal clocking
 }
 
+extern "C" void TPM0_IRQHandler()
+{
+    TPM0->SC = 0; // disable internal clocking
+    TPM0->SC = TPM_SC_TOF_MASK;        
+    RESET_DEBUG;
+    WS2811::dma_done = true;
+}

--- a/WS2811.h	Fri Jan 03 19:17:24 2014 +0000
+++ b/WS2811.h	Sat Jan 04 00:32:16 2014 +0000
@@ -22,6 +22,7 @@
 #define MAX_LEDS_PER_STRIP 60
 
 extern "C" void DMA0_IRQHandler();
+extern "C" void TPM0_IRQHandler();
 
 class WS2811 : public LedStrip
 {
@@ -33,7 +34,6 @@
     virtual void blank();
 
     static void startDMA();
-    static bool is_dma_done();
 
 private:
     uint32_t pinMask;
@@ -44,7 +44,8 @@
 
     static bool initialized;
     static uint32_t enabledPins;
-    static Timer guardtime;
+    static volatile bool dma_done;
+    static void wait_for_dma_done() { while (!dma_done) __WFI(); }
 
     static void writeByte(uint8_t byte, uint32_t mask, uint32_t *dest);
 
@@ -55,7 +56,7 @@
         static void tpm_init();
         static void dma_data_init();
         
-    friend void DMA0_IRQHandler();
+    friend void TPM0_IRQHandler();
 };
 
 #endif

--- a/main.cpp	Fri Jan 03 19:17:24 2014 +0000
+++ b/main.cpp	Sat Jan 04 00:32:16 2014 +0000
@@ -27,6 +27,7 @@
 MMA8451Q acc(PTE25, PTE24, MMA8451_I2C_ADDRESS);
 PwmOut rled(LED_RED);
 PwmOut gled(LED_GREEN);
+// LED_BLUE is on PTD1
 
 float touchPercentage;
 unsigned frames;
@@ -99,7 +100,6 @@
             break;
         }
 
-        wait(0.1);
         showSolidColor(lightStrip1, r, g, b);
         showSolidColor(lightStrip2, r, g, b);
         WS2811::startDMA();