STM32H7's I2C4 using BDMA not triggering Complete Callbacks.

[MLuis.1]

I'm using an STM32H725 to communicate with an i2c sensor. I'm using the I2C4 bus with the HAL DMA functions. I also enabled the BDMA channels for the rx and tx and respective interrupts. The problem is that the complete rx/tx callbacks are not triggered.

I found that this could be related to the problem described here: https://st.my.site.com/community/s/article/FAQ-DMA-is-not-working-on-STM32H7-devices

Any solutions to this problem?

[Foued_KH]

Hello @MLuis.1​ ,

First, make sure that you are using the correct address and the correct frequency for the I²C communication.

The take an oscilloscope to check the I2C_SDA and I2C_SCL behavior to define the error source.

Foued

[MLuis.1]

The I2C communications work fine as long as I use the IT functions or polling functions.

The problem only occurs when using DMA.

[Foued_KH]

You should place the buffer for transmission or reception in the SRAM4.

SRAM4 region : 0x38000000 - 0x38003FFF

Foued

[MLuis.1]

Yes, I thought the same. Any tips on how to do that?

[Foued_KH]

As example :

uint8_t I2C_buffer_Tx[data_size] @ 0x38001000 ;

Foued

[MLuis.1]

The compiler does not accept that syntax.

[Foued_KH]

You can try with this code :

/* Buffer used for transmission */
 
#if defined ( __ICCARM__ )
#pragma location = 0x38000000
uint8_t I2C_buffer_Tx[1] ;
 
#else /* __GNUC__  or __CC_ARM */
uint8_t __attribute__((section (".RAM_D3"))) I2C_buffer_Tx[1]; 
#endif

Foued

[MLuis.1]

Still not working using uint8_t __attribute__((section (".RAM_D3"))) I2C_buffer_Tx[1];

[Foued_KH]

which IDE do you use ?