Hi,
I have adapted the Tivaware example that use the uDMA to transfer to/from the UART to work with the SSI in TI master mode.
I can see on the scope that the TX is sending twice too many words (16bit transfers) and I can't see what I've done wrong. Would be very grateful if someone could check or suggest reason for me.
#define SSI_TXBUF_SIZE 8
static uint16_t SSITXbuf[SSI_TXBUF_SIZE];
The SSI is initialised....
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI0); //fpga spi comms
ROM_SSIDisable(SSI0_BASE); //disable it while we configure it
ROM_GPIOPinConfigure(GPIO_PA2_SSI0CLK);
ROM_GPIOPinConfigure(GPIO_PA3_SSI0FSS);
ROM_GPIOPinConfigure(GPIO_PA4_SSI0RX);
ROM_GPIOPinConfigure(GPIO_PA5_SSI0TX);
ROM_GPIOPinTypeSSI(GPIO_PORTA_BASE, GPIO_PIN_5 | GPIO_PIN_4 | GPIO_PIN_3 | GPIO_PIN_2);
ROM_SSIClockSourceSet(SSI0_BASE, SSI_CLOCK_SYSTEM);
ROM_SSIConfigSetExpClk(SSI0_BASE,
ROM_SysCtlClockGet(),
SSI_FRF_TI,
SSI_MODE_MASTER,
25000000,
16);
ROM_SSIEnable(SSI0_BASE);
ROM_SSIDMAEnable(SSI0_BASE, SSI_DMA_RX | SSI_DMA_TX);
ROM_IntEnable(INT_SSI0);
The uDMA is initialised...
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UDMA);
ROM_uDMAEnable();
ROM_uDMAControlBaseSet(uDmaControlTable);
//rx
ROM_uDMAChannelAttributeDisable(UDMA_CHANNEL_SSI0RX, UDMA_ATTR_ALTSELECT | UDMA_ATTR_USEBURST | UDMA_ATTR_HIGH_PRIORITY | UDMA_ATTR_REQMASK);
ROM_uDMAChannelControlSet(UDMA_CHANNEL_SSI0RX | UDMA_PRI_SELECT,
UDMA_SIZE_16 | UDMA_SRC_INC_NONE | UDMA_DST_INC_16 | UDMA_ARB_4);
ROM_uDMAChannelControlSet(UDMA_CHANNEL_SSI0RX | UDMA_ALT_SELECT,
UDMA_SIZE_16 | UDMA_SRC_INC_NONE | UDMA_DST_INC_16 | UDMA_ARB_4);
ROM_uDMAChannelTransferSet(UDMA_CHANNEL_SSI0RX | UDMA_PRI_SELECT,
UDMA_MODE_PINGPONG,
(void *)(SSI0_BASE + SSI_O_DR),
SSIRXbufA,
sizeof(SSIRXbufA));
ROM_uDMAChannelTransferSet(UDMA_CHANNEL_SSI0RX | UDMA_ALT_SELECT,
UDMA_MODE_PINGPONG,
(void *)(SSI0_BASE + SSI_O_DR),
SSIRXbufB,
sizeof(SSIRXbufB));
ROM_uDMAChannelEnable(UDMA_CHANNEL_SSI0RX);
//tx
ROM_uDMAChannelAttributeDisable(UDMA_CHANNEL_SSI0TX,
UDMA_ATTR_ALTSELECT | UDMA_ATTR_HIGH_PRIORITY | UDMA_ATTR_REQMASK | UDMA_ATTR_USEBURST);
ROM_uDMAChannelControlSet(UDMA_CHANNEL_SSI0TX | UDMA_PRI_SELECT,
UDMA_SIZE_16 | UDMA_SRC_INC_16 | UDMA_DST_INC_NONE | UDMA_ARB_4);
ROM_uDMAChannelTransferSet(UDMA_CHANNEL_SSI0TX | UDMA_PRI_SELECT,
UDMA_MODE_BASIC,
SSITXbuf,
(void *)(SSI0_BASE + SSI_O_DR),
sizeof(SSITXbuf));
ROM_uDMAChannelEnable(UDMA_CHANNEL_SSI0TX);
The SSI interrupt handler for the TX is...
if(!ROM_uDMAChannelIsEnabled(UDMA_CHANNEL_SSI0TX)) { //if finished, start another for test
ROM_uDMAChannelTransferSet(UDMA_CHANNEL_SSI0TX | UDMA_PRI_SELECT,
UDMA_MODE_BASIC, SSITXbuf,
(void *)(SSI0_BASE + SSI_O_DR),
sizeof(SSITXbuf));
for(i=0;i<SSI_TXBUF_SIZE;i++) //init test pattern because TXBUF gets corrupted, why??
SSITXbuf[i] = i+1;
redLedTog; //frame trigger for scope
ROM_uDMAChannelEnable(UDMA_CHANNEL_SSI0TX);
many thanks,
Richard
