STM32F405RG HAL_I2C_Mem_Read_DMA stopped after reading 2 bytes.

[GChen.5]

I was trying to read the 24AA64FT EEPROM using the I2C DMA methods. But the I2C read will break after reading 2 bytes for no reason, and both SDA and SCL stay low. As you can see in the picture, the reading starts with writing 0x50 (0xA0 >> 1) to the EEPROM, then it reads 0x30 and 0x78 and it just stops.

Here is the code, my I2C was configured with STM32CubeMX, I enabled the RX DMA and event/error interrupt.

uint8_t pBuff[64];
memset(pBuff, 0, sizeof(pBuff));
uint8_t res;
// HAL_I2C_Mem_Read works fine
// res = HAL_I2C_Mem_Read(&hi2c1, 0xA0, 0, I2C_MEMADD_SIZE_16BIT, pBuff, 64, 100);
// HAL_I2C_Mem_Read_DMA will stop after reading 2 bytes
res = HAL_I2C_Mem_Read_DMA(&hi2c1, 0xA0, 0, I2C_MEMADD_SIZE_16BIT, pBuff, 64);

 

Here is the result for HAL_I2C_Mem_Read, there is no problem.

[waclawek.jan · Accepted solution]

Maybe consequence of CubeMX incorrectly ordering initialization of DMA https://community.st.com/s/question/0D50X0000Bmob3uSQA/dma-not-working-in-cubemx-generated-code-order-of-initialization ?

JW

[GChen.5]

Thank you! It is the CubeMX init order problem.

[GChen.5]

I solved the problem by place the DMA init before I2C init.

MX_GPIO_Init();
MX_DMA_Init();
MX_I2C1_Init();

I'm using the STM32CubeMX 6.3.0 Linux version. Hope this problem will be fixed in the future.

[Imen.D]

Hello @GChen.5​ ,

This problem will be fixed in the next release of CubeMx.

Thanks for your contribution.

Imen