problems when transmit one byte by uart edma mode

Hello Yang,

Sorry for replying late.

yang lin said:

according to starterware uart_edma, emda can not gernerate tx event after one and only one byte had been transmitted.

I did not understand the background of your above comment. Can you share the UART and EDMA configurations you are using? If you are using FIFO mode, also share the FIFO configurations.

Thanks and Regards.

Gurudutt.

hello

thanks for replying.

what I mean is that I tried the example project "uart_edma" from STARTERWARE-AM335X v2.00.00.07, and the results in no difference.

It is uart0 without fifo.

whenever I called the function below with length = 1,one byte was sent,but any invoking after this with any length, nothing was sent.

if length >=2, nothing wrong happens.

UartEDMATxConfTransfer(unsigned int tccNum,unsigned int chNum,volatile unsigned char *txBuffer,unsigned int length);

/* Transmit DMA Threshold Value. */
#define TX_DMA_THRESHOLD (8u)

/* Receive DMA Threshold Value. */
#define RX_DMA_THRESHOLD (1u)

/* Receiver Buffer Size. */
#define RX_BUFFER_SIZE (8u)

/* EDMA3 Event queue number. */
#define EVT_QUEUE_NUM (0u)

/* PaRAM Set number for Dummy Transfer. */
#define DUMMY_CH_NUM (5u)

/* Wrapper Definitions. */
#define UART_INSTANCE_BASE_ADD (SOC_UART_0_REGS)
#define EDMA3_UART_TX_CHA_NUM (EDMA3_CHA_UART0_TX)
#define EDMA3_UART_RX_CHA_NUM (EDMA3_CHA_UART0_RX)
#define UART_INT_NUM (SYS_INT_UART0INT)

static void UartEDMARxConfTransfer(unsigned int tccNum,
unsigned int chNum,
volatile unsigned char *rxBuffer,
unsigned int length)
{
EDMA3CCPaRAMEntry paramSet;

/* Fill the PaRAM Set with transfer specific information */
paramSet.srcAddr = (unsigned int)UART_THR_RHR_REG;
paramSet.destAddr = (unsigned int) rxBuffer;

/* A, B and C Count values. */
paramSet.aCnt = (unsigned short)RX_DMA_THRESHOLD;
paramSet.bCnt = (unsigned short)length/RX_DMA_THRESHOLD;
paramSet.cCnt = 1;
paramSet.destBIdx = (short)RX_DMA_THRESHOLD;

paramSet.srcBIdx = 0;
paramSet.srcCIdx = 0;
paramSet.destCIdx = 0;

paramSet.linkAddr = 0xFFFF;
paramSet.bCntReload = 0;

/* OPT PaRAM Entries. */
paramSet.opt = 0x00000000u;

/* Source and Destination addressing modes are Incremental. */

/* Setting the Transfer Complete Code(TCC). */
paramSet.opt |= ((tccNum << EDMA3CC_OPT_TCC_SHIFT) & EDMA3CC_OPT_TCC);

/* Enabling the Completion Interrupt. */
paramSet.opt |= (1 << EDMA3CC_OPT_TCINTEN_SHIFT);

/* Now write the PaRAM Set */
EDMA3SetPaRAM(SOC_EDMA30CC_0_REGS, chNum, &paramSet);

/* Enable EDMA Transfer */
EDMA3EnableTransfer(SOC_EDMA30CC_0_REGS, chNum, EDMA3_TRIG_MODE_EVENT);
}