Fix rising/falling edge capture

[~andy/csm213a-hw] / hw2 / timer_dma.c

diff --git a/hw2/timer_dma.c b/hw2/timer_dma.c
index f80572e51fad8956f02879e5728f58d031bd7aab..36fdc979e567527600268f1c27360c187460041b 100644 (file)
--- a/hw2/timer_dma.c
+++ b/hw2/timer_dma.c
@@ -49,6 +49,10 @@ static tdma_t tdma_ports[TDMA_NUM_CHAN];
 /* Global timer initialization */\r
 void tdma_init(void)\r
 {\r
+       static int tdma_init_done = 0;\r
+       if (tdma_init_done)\r
+               return;\r
+\r
        // Enable DMA Cock\r
        SIM->SCGC5 |= SIM_SCGC5_PORTA_MASK;\r
        SIM->SCGC5 |= SIM_SCGC5_PORTC_MASK;\r
@@ -73,6 +77,9 @@ void tdma_init(void)
        // Start timers\r
        PIT->CHANNEL[0].TCTRL |= PIT_TCTRL_TEN_MASK;\r
        PIT->CHANNEL[1].TCTRL |= PIT_TCTRL_TEN_MASK;\r
+\r
+       // Done\r
+       tdma_init_done = 1;\r
 }\r
 \r
 /* DMA Functions */\r
@@ -82,7 +89,10 @@ tdma_t *tdma_open(tdma_chan_t chan, int alt, PinName pin, PinMode mode)
                   pin >= PTC0 ? TDMA_REQ_PTC :\r
                   pin >= PTA0 ? TDMA_REQ_PTA : 0;\r
 \r
-       int irqc = mode == PullUp ? 1 : 2;\r
+       int irqc = mode == PullDown ? 1 : 2;\r
+\r
+       // Initialize global registers\r
+       tdma_init();\r
 \r
        // Allocate port\r
        tdma_t *port    = &tdma_ports[chan];\r