Zoltan Hudak / MODDMA

Fork of Andy Kirkham's MODDMA GPDMA Controller for Mbed OS 6

Read MODDMA for more info.

example3.h@12:1dfee7208043, 2011-03-13 (annotated)

Committer:
AjK
Date:
Sun Mar 13 23:28:21 2011 +0000
Revision:
12:1dfee7208043
Child:
13:846c8b6ffb7f
1.8 See ChangeLog.c

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AjK 12:1dfee7208043 1 /*
AjK 12:1dfee7208043 2 * Demonstrates capturing the GPIO P0.4 to P0.7 "nibble" to memory
AjK 12:1dfee7208043 3 * using GPDMA. The transfers from port pins to memory buffer are
AjK 12:1dfee7208043 4 * triggered using Timer1 MAT1.0 match compare.
AjK 12:1dfee7208043 5 *
AjK 12:1dfee7208043 6 * In this example all inputs have pullups. So with nothing connected
AjK 12:1dfee7208043 7 * the P0.4/7 reads as 0xF. Connecting a wire from one or more of the four
AjK 12:1dfee7208043 8 * inputs to ground will show up in the captured buffer sequence.
AjK 12:1dfee7208043 9 */
AjK 12:1dfee7208043 10
AjK 12:1dfee7208043 11 #include "mbed.h"
AjK 12:1dfee7208043 12 #include "MODDMA.h"
AjK 12:1dfee7208043 13 #include "iomacros.h" // within MODDMA library.
AjK 12:1dfee7208043 14
AjK 12:1dfee7208043 15 // How long between grabbing GPIO FIO0PIN register.
AjK 12:1dfee7208043 16 // Value is in microseconds. (50000 is half a second).
AjK 12:1dfee7208043 17 #define SAMPLE_PERIOD 500000
AjK 12:1dfee7208043 18
AjK 12:1dfee7208043 19 #define NUM_OF_SAMPLES 5
AjK 12:1dfee7208043 20
AjK 12:1dfee7208043 21 Serial pc(USBTX, USBRX);
AjK 12:1dfee7208043 22
AjK 12:1dfee7208043 23 DigitalOut led1(LED1);
AjK 12:1dfee7208043 24 DigitalOut led2(LED2);
AjK 12:1dfee7208043 25 DigitalOut led3(LED3);
AjK 12:1dfee7208043 26
AjK 12:1dfee7208043 27 uint32_t buffer[NUM_OF_SAMPLES];
AjK 12:1dfee7208043 28
AjK 12:1dfee7208043 29 bool dmaTransferComplete;
AjK 12:1dfee7208043 30
AjK 12:1dfee7208043 31 MODDMA dma;
AjK 12:1dfee7208043 32 MODDMA_Config *conf;
AjK 12:1dfee7208043 33
AjK 12:1dfee7208043 34 void TC0_callback(void);
AjK 12:1dfee7208043 35 void ERR0_callback(void);
AjK 12:1dfee7208043 36
AjK 12:1dfee7208043 37 int main() {
AjK 12:1dfee7208043 38
AjK 12:1dfee7208043 39 // Macros defined in iomacros.h, saves messing with DigitalIn
AjK 12:1dfee7208043 40 p30_AS_INPUT; p30_MODE( PIN_PULLUP ); // P0.4
AjK 12:1dfee7208043 41 p29_AS_INPUT; p29_MODE( PIN_PULLUP ); // P0.5
AjK 12:1dfee7208043 42 p8_AS_INPUT; p8_MODE( PIN_PULLUP ); // P0.6
AjK 12:1dfee7208043 43 p7_AS_INPUT; p7_MODE( PIN_PULLUP ); // P0.7
AjK 12:1dfee7208043 44
AjK 12:1dfee7208043 45 // Clear the buffer.
AjK 12:1dfee7208043 46 memset(buffer, 0, sizeof(buffer));
AjK 12:1dfee7208043 47
AjK 12:1dfee7208043 48 // Setup the serial port to print out results.
AjK 12:1dfee7208043 49 pc.baud(115200);
AjK 12:1dfee7208043 50 pc.printf("Starting up...\n");
AjK 12:1dfee7208043 51
AjK 12:1dfee7208043 52 // Set-up timer1 as a periodic timer.
AjK 12:1dfee7208043 53 LPC_SC->PCONP |= (1UL << 2); // TIM1 On
AjK 12:1dfee7208043 54 LPC_SC->PCLKSEL0 |= (3UL << 4); // CCLK/8 = 12MHz
AjK 12:1dfee7208043 55 LPC_TIM1->PR = 11; // TC clocks at 1MHz.
AjK 12:1dfee7208043 56 LPC_TIM1->MCR = 2; // Reset TCR to zero on match.
AjK 12:1dfee7208043 57 LPC_TIM1->MR0 = SAMPLE_PERIOD;
AjK 12:1dfee7208043 58
AjK 12:1dfee7208043 59 // Prepare the GPDMA system.
AjK 12:1dfee7208043 60 conf = new MODDMA_Config;
AjK 12:1dfee7208043 61 conf
AjK 12:1dfee7208043 62 ->channelNum ( MODDMA::Channel_0 )
AjK 12:1dfee7208043 63 ->srcMemAddr ( (uint32_t)&LPC_GPIO0->FIOPIN )
AjK 12:1dfee7208043 64 ->dstMemAddr ( (uint32_t)&buffer[0] )
AjK 12:1dfee7208043 65 ->transferSize ( NUM_OF_SAMPLES )
AjK 12:1dfee7208043 66 ->transferType ( MODDMA::g2m ) // pseudo transfer code MODDMA understands.
AjK 12:1dfee7208043 67 ->transferWidth ( MODDMA::word )
AjK 12:1dfee7208043 68 ->srcConn ( MODDMA::MAT1_0 )
AjK 12:1dfee7208043 69 ->dmacSync ( MODDMA::MAT1_0 )
AjK 12:1dfee7208043 70 ->attach_tc ( TC0_callback )
AjK 12:1dfee7208043 71 ->attach_err ( ERR0_callback )
AjK 12:1dfee7208043 72 ; // end conf.
AjK 12:1dfee7208043 73
AjK 12:1dfee7208043 74 // Prepare configuration.
AjK 12:1dfee7208043 75 if (!dma.Setup( conf )) {
AjK 12:1dfee7208043 76 error("Doh!");
AjK 12:1dfee7208043 77 }
AjK 12:1dfee7208043 78
AjK 12:1dfee7208043 79 // Enable GPDMA to be ready for the TIM1 "ticks".
AjK 12:1dfee7208043 80 dma.Enable( conf );
AjK 12:1dfee7208043 81
AjK 12:1dfee7208043 82 // Begin.
AjK 12:1dfee7208043 83 LPC_TIM1->TCR = 1;
AjK 12:1dfee7208043 84
AjK 12:1dfee7208043 85 while (1) {
AjK 12:1dfee7208043 86 led1 = !led1; // Show some sort of life.
AjK 12:1dfee7208043 87
AjK 12:1dfee7208043 88 if (dmaTransferComplete) {
AjK 12:1dfee7208043 89 dmaTransferComplete = false;
AjK 12:1dfee7208043 90 for (int i = 0; i < NUM_OF_SAMPLES; i++) {
AjK 12:1dfee7208043 91 int val = (buffer[i] >> 4) & 0xF;
AjK 12:1dfee7208043 92 pc.printf("Buffer index %d = 0x%x\n", i, val);
AjK 12:1dfee7208043 93 }
AjK 12:1dfee7208043 94 pc.printf("Done.\n");
AjK 12:1dfee7208043 95 }
AjK 12:1dfee7208043 96 }
AjK 12:1dfee7208043 97 }
AjK 12:1dfee7208043 98
AjK 12:1dfee7208043 99 // Configuration callback on TC
AjK 12:1dfee7208043 100 void TC0_callback(void) {
AjK 12:1dfee7208043 101
AjK 12:1dfee7208043 102 // Just show sample sequence grab complete.
AjK 12:1dfee7208043 103 led3 = !led3;
AjK 12:1dfee7208043 104
AjK 12:1dfee7208043 105 // Disable firing timer.
AjK 12:1dfee7208043 106 LPC_TIM1->TCR = 0;
AjK 12:1dfee7208043 107
AjK 12:1dfee7208043 108 // Get configuration pointer.
AjK 12:1dfee7208043 109 MODDMA_Config *config = dma.getConfig();
AjK 12:1dfee7208043 110
AjK 12:1dfee7208043 111 // Finish the DMA cycle by shutting down the channel.
AjK 12:1dfee7208043 112 dma.Disable( (MODDMA::CHANNELS)config->channelNum() );
AjK 12:1dfee7208043 113
AjK 12:1dfee7208043 114 // Tell main() while(1) loop to print the results.
AjK 12:1dfee7208043 115 dmaTransferComplete = true;
AjK 12:1dfee7208043 116
AjK 12:1dfee7208043 117 // Clear DMA IRQ flags.
AjK 12:1dfee7208043 118 if (dma.irqType() == MODDMA::TcIrq) dma.clearTcIrq();
AjK 12:1dfee7208043 119 if (dma.irqType() == MODDMA::ErrIrq) dma.clearErrIrq();
AjK 12:1dfee7208043 120 }
AjK 12:1dfee7208043 121
AjK 12:1dfee7208043 122 // Configuration callback on Error
AjK 12:1dfee7208043 123 void ERR0_callback(void) {
AjK 12:1dfee7208043 124 error("Oh no! My Mbed EXPLODED! :( Only kidding, go find the problem");
AjK 12:1dfee7208043 125 }