flash loader demo works only with legacy serial port

mehmet.karakaya · ‎2011-01-31

Posted on January 31, 2011 at 19:05

gmamo · ‎2011-05-17

Posted on May 17, 2011 at 14:23

You mean.. into the rs232 DB9 of your development board ??

If yes, then it's because probably your UART to USB is not rs232 compliant in terms of the voltages specified in the rs-232 protocol.

Try bypassing your UART-USB into the TX and RX of your microcontroller.

Try this mod at your own risk.

chikos332 · ‎2011-05-17

Posted on May 17, 2011 at 14:23

Hi,

try to add a pull-up resistance (~50KOhm) on the device TX line it should work.

try it on your own risk, and be careful not to cause a short-circuit.

Cheers.

Tesla DeLorean · ‎2011-05-17

Posted on May 17, 2011 at 14:23

I'm using USB-to-serial adapters to program the STM32's without any real problems.

I had to mod the software to handle serial ports >COM9 but intrinsically from the STM32's perspective this is a PC coding issue and not a problem with the boot loader.

It could be that your USB-to-serial adapters suck, some can be pretty cheap and awful. The ones from DLP seem to be quite robust.

It could be that your RS232-to-CMOS conversion isn't optimal, or well suited to your USB-to-RS232 adapters implementation.

You could try a different brand / model of adapter. You could try different baud rates. The STM32 auto-bauds when booted into the loader. You could try putting a scope on the signals and compare/contrast them between the PC RS232 and the USB RS232.

This might be something you need to get your hand dirty and test your implementation, because I'm pretty sure it's not intrinsic to the STM32.

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mehmet.karakaya · ‎2011-05-17

Posted on May 17, 2011 at 14:23

hello,

I have a MAX232 IC on my board - you mean on the RS232_TX line ? where do I pull the line up ? to ( pin +10V ) of MAX232 ?

2 ) or on the STM32_TX line ? the MAX232 has already 400 K internall pullups to 5 volt

trevor23 · ‎2011-05-17

Posted on May 17, 2011 at 14:23

I remember having a problem with flash loader if the serial port number was too large (more than 9 I think). You can force your USB to serial converter to be allocated a lower number: ''Device Manager'' - ''ports''.

This may have been fixed in more recent versions but worth a try if your port number is large.

mehmet.karakaya · ‎2011-05-17

Posted on May 17, 2011 at 14:23

hello , what is strange is

that my application program can comunicate with USART1 <-> USB-serial succesfully

but the same USART1 cannot comunicate in flash loader mode with USB-serial

I also experienced that flash loader only comunicates with very fast core 2 duo PC

it doesnot comunicate with slower pentium-3 PC ( even legacy port )