stm32f4discovery bootloader

[mwolke9]

Posted on August 31, 2012 at 15:23

I have a porblem with the stm32f4 bootloader!

The initialisation of the bootloader via

USART1 (PA9/PA10) works so far.

I am using a stm32f4discovery-board.

The problem ist that it only works with very low baudrates.

I connected PB5, PC11 and PB11 to GND so that none of them  toggles.

Furthermore I connected BOOT1 to GND and BOOT0 to 3,3 V before entering the bootloader-mode by pulling the NRST-PIN to GND for a short time.

H-TERM:

If I send 0x7F with a baudrate of 2400 I recive an ACK (0x79) so there is no problem with flashing.

With a higher baudrate of 4800 it doesn’t send 0x79 as an answer  but 0xFE.

Moreover:

Baud 9600:  0xFF

Baud 14400: no response

I supposed there is a problem with the autobaudrateadaption!

Using the bootloader demonstrator:

Baud 2400: recognized device

Until Baud 9600: unrecognized device

From Baud 14400: no response from target

First I used usb-ttl-converter.

Using a rs232-ttl-converter didn´t help although I measured the boudrate and it is exact !

So is there a way to increse the possible baudrate?

What might be the problem?

Thanks for your help!

[Tesla DeLorean]

Posted on August 31, 2012 at 20:19

Make sure you have it set for EVEN parity ie 8-E-1

[mwolke9]

Posted on September 03, 2012 at 09:53

My settings:

8 databits

1 stopbit

parity even

[mwolke9]

Posted on September 03, 2012 at 10:02

and of course one start bit...

Bootloader demonstrator has the right settings and it also doesn´t work with high baud rates. Are there any other sugestions?

[mwolke9]

Posted on September 04, 2012 at 09:29

I tried the same settings with the stm32f0discovery and there is no problem with baudrates of 115200. moreover i baught another stm32f4discovery to make sure it isn´t broken. the same problem acures

[Tesla DeLorean]

Posted on September 04, 2012 at 21:08

Use USART3 (PB.10, PB.11), these definitely work up to 115200,8E1

The PA.9 and PA.10 are used on the STM32F4-Discovery for the USB (VBUS, ID) functions. These do appear to conflict with desired operation.

[mwolke9]

Posted on September 26, 2012 at 16:03

First there is a conflict of the C49 wich functions as lowpassfilter and wich doesn´t alow high baud rates. So it has to be removed! In the best case you have to connect the OUT-pin of the STMPS2141STR and the VBUS of USB without having any connection to PA9 if a use of USB

and

USART1 is nessesary. Second point is that R59 has to be taken from the Board so that the ID-pin of the USB and the PA10 do not conflict! While entering bootmode the DM-pin and the DP-pin of the USB have to be pulled LOW so that the USB is not recognized as bootdevice!