STM32L496 I2C1/3 cannot work on GPIOG port.

[ray]

Posted on April 08, 2018 at 09:13

L496 port G includes two I2C- PG13/14 I2C1 and PG7/8 I2C3. But the two I2C cannot output and the oscilloscope does not display waveform.

I2C1/I2C3 can work correctly if they are mapped to other ports. So I think the I2C1/I2C3 modules are ok in L496.

On the other hand, if I set PG13/14 and PG7/8 pin mode as GPIO output, they can work well. So the GPIOG module is ok.

So what is the problem with GPIOG I2C? I know Port G[15:2] are independent from other ports. But I connect Vddio2 to Vdd in the test. Please see the code below.

Init Code:

LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOG);

HAL_PWREx_EnableVddIO2();

LL_GPIO_SetPinMode(GPIOG, LL_GPIO_PIN_13, LL_GPIO_MODE_ALTERNATE);

LL_GPIO_SetAFPin_0_7(GPIOG, LL_GPIO_PIN_13, LL_GPIO_AF_4);

LL_GPIO_SetPinSpeed(GPIOG, LL_GPIO_PIN_13, LL_GPIO_SPEED_FREQ_HIGH);

LL_GPIO_SetPinOutputType(GPIOG, LL_GPIO_PIN_13, LL_GPIO_OUTPUT_OPENDRAIN);

LL_GPIO_SetPinPull(GPIOG, LL_GPIO_PIN_13, LL_GPIO_PULL_UP);

LL_GPIO_SetPinMode(GPIOG, LL_GPIO_PIN_14, LL_GPIO_MODE_ALTERNATE);

LL_GPIO_SetAFPin_0_7(GPIOG, LL_GPIO_PIN_14, LL_GPIO_AF_4);

LL_GPIO_SetPinSpeed(GPIOG, LL_GPIO_PIN_14, LL_GPIO_SPEED_FREQ_HIGH);

LL_GPIO_SetPinOutputType(GPIOG, LL_GPIO_PIN_14, LL_GPIO_OUTPUT_OPENDRAIN);

LL_GPIO_SetPinPull(GPIOG, LL_GPIO_PIN_14, LL_GPIO_PULL_UP);

Read Code:

LL_I2C_Enable(I2C1);

LL_I2C_HandleTransfer(I2C1, add, LL_I2C_ADDRSLAVE_7BIT, 2, LL_I2C_MODE_AUTOEND, LL_I2C_GENERATE_START_READ);

while (!LL_I2C_IsActiveFlag_STOP(I2C1))

{

if (LL_I2C_IsActiveFlag_RXNE(I2C1))

{

i2c1Ctx.rxBuffer[0] = LL_I2C_ReceiveData8(I2C1);

}

}

LL_I2C_ClearFlag_STOP(I2C1);

[Tesla DeLorean]

Posted on April 08, 2018 at 16:41

Make sure the PWR peripheral's clock is enabled

LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_PWR);

You want code equivalent to

   /* VddIO2 must be enabled to access GPIO port G[2:15] */

   __HAL_RCC_PWR_CLK_ENABLE();

   HAL_PWREx_EnableVddIO2();

   __HAL_RCC_GPIOG_CLK_ENABLE();

[ray]

Posted on April 12, 2018 at 12:27

Thanks Clive. I use HAL driver and it can work now. It would be some I2C setting problems in LL library. 

Actually I don't want to use HAL because it's too big and inefficient.  Thanks your help again.

[Amel NASRI]

Posted on April 12, 2018 at 17:33

Hi

Mei.Raymond

‌,

Could you please explain how you did resolved the issue with pins in port G to be used with I2C?

Thanks.

-Amel

[ray]

Posted on April 13, 2018 at 02:57

I just used the demo in your Nucleo package,

STM32Cube_FW_L4_V1.10.0\Projects\STM32L496ZG-Nucleo\Examples\I2C\I2C_TwoBoards_ComPolling

I have not compared the detail difference in HAL and LL library for I2C setting. I think it is a bug to config Port G I2C1/3 in LL. Hope ST can fix it in the future. Thanks.

[Theo Hussey]

Posted on June 06, 2018 at 15:32

If you are setting a GPIO pin greater than 7 to an alternate function, you need to use the LL_GPIO_SetAFPin_8_15 function. eg.

LL_GPIO_SetAFPin_8_15(GPIOG,

LL_GPIO_PIN_13

, LL_GPIO_AF_4);