Slow performance of custom external flash loader on STM32H735G-DK.

[AS1956]

            I made external flash loader for STM32H735G-DK. I’m able to read, write and erase flash. However, programming 1M of flash takes ~ 50 seconds. STM provided loader takes around 7 sec for the same. Octo SPI in both cases, clocks are the same- verified, DTR in both cases- verified. I am testing on the same board, the same STLINK, so hardware is not limiting factor.

Would anyone have an idea what method STM loader uses for such a huge speed improvement?

[LCE]

Maybe you are using some blocking HAL stuff?

I would grab a scope and compare some signals.

[Pavel A.]

> STM provided loader takes around 7 sec for the same. 

Does this include erase of 1 MB?

 

[AS1956]

14:59:38 : Memory Programming ...
14:59:38 : Opening and parsing file: testbinary1M.bin
14:59:38 : File : testbinary1M.bin
14:59:38 : Size : 1.13 MB
14:59:38 : Address : 0x90000000
14:59:38 : Erasing memory corresponding to segment 0:
14:59:38 : Erasing external memory sectors [0 18]
14:59:43 : Download in Progress:
14:59:46 : File download complete
14:59:46 : Time elapsed during download operation: 00:00:07.732

 

 

Yes

[Tesla DeLorean]

Hard to know..

ST uses 64KB sector erase, and 1 KB pages.

If ST's is smaller in RAM there is more for payload data. Perhaps less initialization / reset, repeatedly?

Some comparative logs at Verbose Level 3 might be informative.

[AS1956]

logs included, if you wish to take a look.

Thanks

[AS1956]

too fast

[AS1956]

AS per MX25LM51245G data sheet programming page is 256 bytes. Are you saying that somehow ST uses 1KB?

[Tesla DeLorean]

Actually is reports taking multiples of 0x1000 / 4KB (16 x 256) per Write() operation, so there are some operational efficiencies there, it decomposes to 256-byte pages internally.

[LCE]

You haven't told us yet if you are using HAL functions for your own programming.

If yes, go through these and check for while() and HAL_Delay().

And check if you are actually using the flash in octal mode. The speed difference is close to a factor of 8, so maybe you are using it in single bit/IO SPI mode.

[AS1956]

Got 1M programming close to ST loader. 1M programming ~9.5 sec vs ~7 sec with ST loader. It is good enough for now. You guys were right it was HAL issue.

Thank you all that commented.

[LCE]

@AS1956  We are some curious folks here, so could you please give us a hint what the actual problem was and how you solved it? ;) 

Thanks!

[AS1956]

Overwrote __weak void HAL_Delay(uint32_t Delay) with:

void HAL_Delay(uint32_t Delay){

  int i=0;

  for (i=0; i<0x1000; i++);

}

Works well.

[LCE]

Wow, that's ... interesting.

HAL_Delay() is used in many, many HAL functions, so you might "break" other HAL stuff with this modification.

 

[Pavel A.]

"Externa loaders" cannot use interrupts.