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TMS570LC4357: HERCULES TMS570LC43 DMA Send on SCI3 Issue

Michael Bloch
Prodigy 20 points
Part Number: TMS570LC4357
Other Parts Discussed in Thread: HALCOGEN

Device: TMS570LC4357BZWTQQ1

Compiler: TI Clang v2.1.0.LTS, BE32

Issue: when configuring sending serial data buffers on SCI3 using DMA the MSb of the last byte of the buffer is always set on the wire.  The buffer set in g_dmaCTRL does not have the bit set and when sending direct on SCI the bit is not set.  When using DMA the bit is always set, we carry the CRC in the last 2 bytes so it was showing up as intermittent frame errors.

The g_dmaCTRL is set thusly:

g_dmaCTRL dmaControl = {.SADD = address_as_number, .DADD = SCI3_TX_ADDR, .CHCTRL = 0,
.FRCNT = length, .ELCNT = 1, .ELDOFFSET = 0,
.ELSOFFSET = 0, .FRDOFFSET = 0, .FRSOFFSET = 0,
.PORTASGN = PORTA_READ_PORTB_WRITE, .RDSIZE = ACCESS_8_BIT,
.WRSIZE = ACCESS_8_BIT, .TTYPE = FRAME_TRANSFER, .ADDMODERD = ADDR_INC1,
.ADDMODEWR = ADDR_FIXED, .AUTOINIT = AUTOINIT_OFF};

we listed for BTC interrupt to acknowledge the send completed:

dmaEnableInterrupt(DMA_CH0, BTC, DMA_INTA);

I'm not sure where to start tweking to resolve this.  Any insights appreciated.

  • +1
    TI__Guru 62570 points

    Hi Michael,

    Michael Bloch said:
    when configuring sending serial data buffers on SCI3 using DMA the MSb of the last byte of the buffer is always set on the wire.

    If i understand it correctly, no matter what the value of MSb(i.e. either logic-0 or logic-1) it is transmitting as logic-1 to the destination. Is this correct?

    Did you get a chance to verify your code with, example SCI DMA present in HALCoGen?

    If you make sure your code is correct, can you please formward the code? at least a minimal version with only SCI and DMA?

    --

    Thanks & regards,
    Jagadish.