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TMS320F28335: a little problem about DSP28335 SCI_Boot and C2Prog

wenby chen
Prodigy 10 points
Part Number: TMS320F28335

I think there may be a little problem about  DSP28335 SCI_Boot and C2Prog.

TI  Literature Number: SPRU963A  --  TMS320x2833x, 2823x Boot ROM  Reference Guide  ,  this document describes the boot process and source code.
Uint32 SCI_Boot()
{
  ...
  EntryAddr = GetLongData();
  CopyData();
  return EntryAddr;
}
void CopyData()
{
 ...
  for(i = 1; i <= BlockHeader.BlockSize; i++)
 {
  wordData = (*GetWordData)();
  *(Uint16 *)BlockHeader.DestAddr++ = wordData;
 }
 ...
}
Uint16 SCIA_GetWordData()
{
  ...
  while(SciaRegs.SCIRXST.bit.RXRDY != 1) { }
  wordData = (Uint16)SciaRegs.SCIRXBUF.bit.RXDT;
  SciaRegs.SCITXBUF = wordData;
  ...
}
When the code ‘return EntryAddr’  of SCI_Boot() function is being executed, the SCI_A TXSHF Register is not empty.   
Then, if the APP changes the baud rate of SCI_A immediately, the data on TXD Line being sent will be in error.
I use C2Prog V1.7 to update DSP28335 FLASH with rs232,  I get this error.
What I can confirm is that the error occurred just when the boot was completed .
I found the baud rate is changed to 9600 from 38400 .
The oscillogram of that moment is attached .