TMS570LC4357: HERCULES TMS570LC43 DMA Send on SCI3 Issue

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.