I2C4 in ST_STM32F769I_DISCOVERY Topic is solved

[josesimoes]

Hello,

Was trying to use I2C4 on this Discovery board to enable the touch screen controller.
It's throwing a hard fault when calling line 835 @ os\hal\ports\STM32\LLD\I2Cv2\hal_i2c_lld.c

dmaStreamSetPeripheral(i2cp->dmatx, &dp->TXDR);

I've tried to tweak the DMA assignments without success.
If it's worth it I can use I2C1 just fine.

Couldn't find anything that looks obvious to me on what could be causing this.
Any hints?

BTW, I'm using the latest 19.1.3.

Thanks!

[Giovanni]

Could you compile with -O0 and see what exactly is throwing the hard fault?

That function does not touch I2C4, it just sets DMA registers.

Giovanni

[josesimoes]

Giovanni,

I've just compiled with -O0 as suggested. The hard fault is still there, but I couldn't see any indication on what could be causing it...
I do have a fault handler but I couldn't find anything from the output.


In the mean time I've stumbled on this:
viewtopic.php?f=35&t=5443

It's on a different series and I2C driver, I know, but could it be related?
I've checked the vectors myself and haven't found anything suspicious...

[Giovanni]

Hi,

I tried adding an i2cStart() to the RT-STM32F746G-DISCOVERY demo and it goes past i2cStart() without problems. I tested on trunk and the latest 19.1.x.

Could you give trunk code a try? or update to latest 19.1.x which will become 19.1.4 soon.

Giovanni

[josesimoes]

Thanks for looking into this.

I'm already using the latest on 19.1.x...

A question that may be stupid, but just to be sure: your test was with I2C4, correct?

Thanks!

[Giovanni]

Yes, I2CD4.

[Giovanni]

Any news on this?

Giovanni

[josesimoes]

Nope. Keeping throwing a hard fault...

[Abusous2000]

I got it to work on both STM32F746g-discovery and STM32F769i (with LCD & Audio decoder wm8994) on I2C4. Make sure that you have enabled the pins with open drain and highest speed only; and you will be OK

[Giovanni]

Closing until/unless there is confirmation of this problem.

Giovanni