MSP430F5437 UART Rx problem when flashing

Hi,

I am using MSP430F5437 and I am seeing some varying results. I have created code to download firmware upgrades, and this works fine on 3 our of the 4 boards that I have. The processor is running at 18MHz and the baud rate is 115200.

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Clock settings:

 UCSCTL1 |= DISMOD;
  UCSCTL0 = 0x0000;
 
  UCSCTL3 = 0x0020;
 
  __bis_SR_register(SCG0);
 
  UCSCTL1 = DCORSEL_7;                    // Select suitable range
 
  UCSCTL2 = 548 + FLLD_1;         // Set DCO Multiplier
  UCSCTL4 = SELA__REFOCLK | SELS__DCOCLKDIV  |  SELM__DCOCLKDIV ;
 

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UART settings:

UCA1BR0  = 9;             
 UCA1BR1  = 0;
 UCA1MCTL = 0xC1;

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Let me explain what I have done.

With the current code I have setup a test case were data is streamed to the device. All devices can receive hundreds of megabytes without giving me any failures. If I start copying this data from my incoming buffer to flash that is when I get into trouble. 

My flashing routine globally disables interrupts and uses polling on the UART Rx flag to check for incoming bytes (UCA1IFG & UCRXIFG). One test that I did was to replace flashing with delays to simulate the timing, and this test again showed no problems with receiving data. 

I have tried the 3 methods for flashing data. Byte, long word and even block write (128 bytes).

Byte writes are too slow, and even a 4K buffer (About 60K of code) overflows.

Long word writes are fine on 3 out of 4 boards.

Block writes does not seems to work at full speed (Inserting breaks between chars and it does work). Documentation is a little unclear here, as it seems no access to flash can be done while a block write is in progress.

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Summarize:

My current code writes to flash 4 bytes at a time, while receiving data on the UART. 3 devices out of 4 that I are testing have no problems, while a 4th has any of these bits set: UCFE, UCOE, UCRXERR or UCBRK. If flashing is disabled, all boards can receive an endless amount of data without issues, it seems.

Any advice would be much appreciated.

Thanks,

Jorgen