ADC with BLE onSTM32WBA

[Tony_Tony]

Hi,

I want to implement a simple application: ADC conversion and transmit the data via BLE. I achieved to do it on stm32wb15cc development board, but I have problems when trying do implement it on my custom board with stm32wba54. In the codes, I basically do the followings:

1. Start ADC conversion with DMA, triggered by timer.

2. When buffer is full, in conversion complete callback function, register BLE transmission task in sequencer to tranmit buffer data.

On my stm32wba54 board, the buffer won't start filling. I suspect that it's because in wba series, internal temperature sensor needs to enabled for RF calibration and it keeps conflicting with my main ADC channel. How couId I deal with that?

Thank you!

[Remy ISSALYS]

Hello, 

Indeed in BLE applications on STM32WBA, ADC4 is used for temperature measurement which is needed for RF calibration. ADC controller module has been implemented to be able to share ADC usage between the application and the temperature measurement needed for RF calibration. You can look adc_ctrl.c file  in Firmware\Projects\Common\WPAN\Modules. 

Best Regards,

Remy

[Tony_Tony]

Hi Remy,

I did a further test and it turned out that the timer is not working properly. Here is what I did:

1. I initiated a timer with interrpt and created a counter variable to check elapsed periods: 

uint16_t TIM_counter = 0;

HAL_TIM_Base_Start_IT(&htim1); 

3. In period elapsed ccallback function, I increment my counter variable everytime a period elapses:

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
  TIM_counter ++;
}

On nucleo-wb15cc, the counter keeps increment with defined interval. But on my custom board with stm32wba54kgu6, the counter flashes between 1 and 0. It looks like the timer is being reinitialized constantly. This is my timer setup for both stm32wb15cc and stm32wba54:

I wonder what difference between stm32wb15cc and stm32wba54 is causing this problem and how to solve it?

Thanks and best regards!

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Code formatting applied - please see How to insert source code for future reference.

[STTwo-32]

Just a comment. The NUCLEO-WB15CC is based on a STM32WB MCU (Dual core cortex-M4 and Cortex-M0+ MCU). But the STM32WBA54KGU6 is a STM32WBA5 MCU (a Uni core cortex-M33 MCU). So, the Nucleo board that you are using is not the best one to evaluate a code that will be implemented on a STM32WBA54KGU6. You may use the NUCLEO-WBA55CG for more compatibility.

Best Regards.

STTwo-32

[Andrew Neil]

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@Tony_Tony wrote:

1. I initiated a timer with interrpt and created a counter variable to check elapsed periods: 

uint16_t TIM_counter = 0;

Your counter should be volatile.

[Tony_Tony]

That's a good point, but unfortunately didn't solve the problem

[Tony_Tony · Accepted solution]

I found the cause for this issue, it was that the battery voltage dropped below the voltage range of my LDO so that the power supply became unstable. The issue was fixed after I exchanged the battery.