TMS570LC4357: DMA control packet Reconfiguration for variable length SCI Tx data

Hi Miroslav,

!! Thanks you for your support :-) !!

I'm using the DMA for data transmission over the SCI1. Buffer i'm sending on the SCI using DMA is of variable length.

Each time once i received the Block Transfer Complete interrupt (BTC) i will copy the new data in SharedRAM location and calling the below function by passing the length of buffer.

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void Dma_modify_and_send (uint16 packet_size)
{
sciInit();

while (((sciREG1->FLR & SCI_TX_INT) == 0U) || ((sciREG1->FLR & 0x4) == 0x4))
{
} /* Wait */

dmaEnableInterrupt(DMA_CH0,BTC,DMA_INTA);

/*Assign DMA request SCI3 transmit to Channel 0*/
dmaReqAssign(DMA_CH0, DMA_SCI1_TX);

/*Assign DMA request SCI4 receive to Channel 1*/
sciTxData = SCI1_TX_ADDR;

/*Configure control packet for Channel 0*/
g_dmaCTRLPKT1.SADD = (uint32_t)TX_DATA; /* source address */
g_dmaCTRLPKT1.DADD = sciTxData; /* destination address */
g_dmaCTRLPKT1.CHCTRL = 0; /* channel control */
g_dmaCTRLPKT1.FRCNT = packet_size; /* frame count */
g_dmaCTRLPKT1.ELCNT = 1; /* element count */
g_dmaCTRLPKT1.ELDOFFSET = 0; /* element destination offset */
g_dmaCTRLPKT1.ELSOFFSET = 0; /* element destination offset */
g_dmaCTRLPKT1.FRDOFFSET = 0; /* frame destination offset */
g_dmaCTRLPKT1.FRSOFFSET = 0; /* frame destination offset */

g_dmaCTRLPKT1.PORTASGN = PORTA_READ_PORTB_WRITE;
g_dmaCTRLPKT1.RDSIZE = ACCESS_8_BIT; /* read size */
g_dmaCTRLPKT1.WRSIZE = ACCESS_8_BIT; /* write size */
g_dmaCTRLPKT1.TTYPE = FRAME_TRANSFER; /* transfer type */
g_dmaCTRLPKT1.ADDMODERD = ADDR_INC1; /* address mode read */
g_dmaCTRLPKT1.AUTOINIT = AUTOINIT_OFF; /* auto init */

/*Set control packet for channel 0 and 1*/
dmaSetCtrlPacket(DMA_CH0, g_dmaCTRLPKT1);

/*Set dma channel 0 and 1 to trigger on hardware request*/
dmaSetChEnable(DMA_CH0, DMA_HW);

/*Enable DMA*/
dmaEnable();

/*Enable SCI3 Transmit and SCI4 Receive DMA Request*/
sciREG1->SETINT |= SCI_SET_TX_DMA;

}

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Now i have two question :

1) Do i need to call the sciInit(); each time ? if your answer is NO, DMA will not send the subsequent copied buffer and stops the working if did't called the sciInit(); function, is there any solution for that bcoz we should not re-init the sciInit();

2) Do i need to use below complete code each time to configure new control packets. what should be the bare minimum code that i should re-configure ?

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