ADC Scan Mode and PWM Complementary Channel Conflict.

[prometus]

(MCU:STM8AF6223A-TSSOP20 MCU Label: STM8AF6223PDX
Library: SPL V2.2.0

Compiler SDCC:4.5.0 Debugger:stm8-gdb 8.1

Custom Makefile
MCU uses internal oscillator runnnig 16 MHz)

Hi I'm Attila.

When I enable the ADC1 Scan Mode and DataBuffer with ADC_Channel >= ADC1_CHANNEL_2 TIM1_CH2N waveform distorted.

Oscilloscope CH1(Yellow) -> TIM1_CH1N
Oscilloscope CH1(Light Blue) -> TIM1_CH2N

For example when ADC_Init() with ADC1_CHANNEL_2

when ADC_Init() with ADC1_CHANNEL_1

ADC1_CHANNEL_2 is the AIN2 but Before the operation, i program the option bytes for enable the complementary channels.

What causes the distortion?

Best regards.

Bonus.

I also try disable TIM1_CH2N with TIM1_OC2Init() function i realized that ADC sampling effect that pin .

Some piece of code 

 

void main(void)
{
 CLK_HSIPrescalerConfig(CLK_PRESCALER_HSIDIV1);
 ADC_Config();
 TIM1_Config();
 ITC_SetSoftwarePriority(ITC_IRQ_ADC1, ITC_PRIORITYLEVEL_2); 
 TIM1_Cmd(ENABLE);
 TIM1_CtrlPWMOutputs(ENABLE);
 TIM1_SetCompare1(66);
 TIM1_SetCompare2(376);
 TIM1_SetCompare3(1);

}

static void ADC_Config()
{
 /* Init GPIO for ADC1 */
 GPIO_Init(GPIOD, GPIO_PIN_2, GPIO_MODE_IN_FL_NO_IT);

 GPIO_Init(GPIOD, GPIO_PIN_3, GPIO_MODE_IN_FL_NO_IT); //20.pin for reading negative current

 /* De-Init ADC peripheral*/
 ADC1_DeInit();

 /* Init ADC2 peripheral */
 ADC1_Init(ADC1_CONVERSIONMODE_SINGLE/*ADC1_CONVERSIONMODE_CONTINUOUS*/, ADC1_CHANNEL_2, ADC1_PRESSEL_FCPU_D2,
 ADC1_EXTTRIG_TIM, /*DISABLE*/ENABLE, ADC1_ALIGN_RIGHT, ADC1_SCHMITTTRIG_ALL,
 DISABLE);
 
 /* Enable scan mode and buffering */
 ADC1_ScanModeCmd(ENABLE);
 ADC1_DataBufferCmd(ENABLE);

 /* Enable EOC interrupt */
 ADC1_ITConfig(ADC1_IT_EOCIE, ENABLE); // not ADC1_IT_EOC
 ADC1_Cmd(ENABLE);
 ADC1_SchmittTriggerConfig(ADC1_SCHMITTTRIG_ALL, DISABLE); // explicitly disable Schmitt on AIN2 = PC4

 ADC1_StartConversion();

}

static void TIM1_Config(void)
{
 TIM1_DeInit();
 CLK_PeripheralClockConfig(CLK_PERIPHERAL_TIMER1, ENABLE); 
 GPIO_Init(GPIOC, GPIO_PIN_6, GPIO_MODE_OUT_PP_HIGH_FAST); // CH1
 GPIO_Init(GPIOC, GPIO_PIN_3, GPIO_MODE_OUT_PP_LOW_FAST); // CH1N
 GPIO_Init(GPIOC, GPIO_PIN_7, GPIO_MODE_OUT_PP_HIGH_FAST); // CH2
 GPIO_Init(GPIOC, GPIO_PIN_4, GPIO_MODE_OUT_PP_LOW_FAST); // CH2N
 TIM1_TimeBaseInit(0, COUNTER_MODE, TIM_PERIOD, PWM_REPETITION_COUNTER);

 TIM1_OC1Init(
 TIM1_OCMODE_PWM2,
 TIM1_OUTPUTSTATE_ENABLE,
 TIM1_OUTPUTNSTATE_ENABLE,
 0, // CCR2
 TIM1_OCPOLARITY_HIGH,
 TIM1_OCNPOLARITY_HIGH,
 TIM1_OCIDLESTATE_RESET,
 TIM1_OCNIDLESTATE_SET
 );

 TIM1_OC1PreloadConfig(ENABLE);

 TIM1_OC2Init(
 TIM1_OCMODE_PWM2,
 TIM1_OUTPUTSTATE_ENABLE,
 TIM1_OUTPUTNSTATE_ENABLE,
 0, // CCR2
 TIM1_OCPOLARITY_HIGH,
 TIM1_OCNPOLARITY_HIGH,
 TIM1_OCIDLESTATE_RESET,
 TIM1_OCNIDLESTATE_SET
 );

TIM1_OC2PreloadConfig(ENABLE);
TIM1_OC3Init(TIM1_OCMODE_PWM1, TIM1_OUTPUTSTATE_DISABLE, TIM1_OUTPUTNSTATE_DISABLE, (uint16_t)1, TIM1_OCPOLARITY_HIGH, TIM1_OCNPOLARITY_HIGH, TIM1_OCIDLESTATE_RESET, TIM1_OCNIDLESTATE_RESET);
TIM1_OC3PreloadConfig(ENABLE);

 TIM1_BDTRConfig(
 TIM1_OSSISTATE_DISABLE, // OSSI (off-state selection for idle mode)
 TIM1_LOCKLEVEL_1,
 8, // Deadtime 
 TIM1_BREAK_DISABLE, // Break enable
 TIM1_BREAKPOLARITY_LOW, // Break polarity
 TIM1_AUTOMATICOUTPUT_ENABLE // Automatic output enable
);

 TIM1_SelectOutputTrigger(TIM1_TRGOSOURCE_OC3REF);

}

INTERRUPT_HANDLER(ADC1_IRQHandler, 22)
{
 if (ADC1_GetFlagStatus(ADC1_FLAG_EOC) == SET)
 {
 value_pos = ADC1_GetBufferValue(3); // AIN3 (positive current)
 value_neg = ADC1_GetBufferValue(4); // AIN4 (negative current)

 adc_sample_counter += 1u;

 ADC1_ClearFlag(ADC1_FLAG_EOC);
 if (ADC1_GetFlagStatus(ADC1_FLAG_OVR) == SET) {
 ADC1_ClearFlag(ADC1_FLAG_OVR); // Handle potential overrun
 }
 }
}

 

 

 

[prometus]

Edit: I put the wrong MCU picture. Take care this. 

[AScha.3]

Hi,

so you switching on same pin between two functions : adc in vs pwm out .

>What causes the distortion?

You , by using one pin on two functions and switching between them.

So decide to use the pin for one of the possible functions and you get this function without "distortion".

+

ADC sampling on a (open) pin has to give some "effect" , as the adc input (sampling cap ) is switched to the pin , to be charged here; thats why any pin to be read needs some capacity to GND or low driving impedance (from opamp or esle..).

[prometus]

Hi, i think you misinterpret, 

I configure PC4 as a CH1_CH2N.(Its alternating property is AIN2 but i didn't configure it to ADC)(before, i program option bytes to enable complementary channel)

GPIO_Init(GPIOC, GPIO_PIN_4, GPIO_MODE_OUT_PP_LOW_FAST); // CH2N

 I want to use PD3 pin as a analog configruation -> AIN4

I can able to read PD2 (AIN3) but when i need to get AIN4 and AIN3 same time i enable ADC scan mode 

But when i calling this for this purpose 

 ADC1_Init(ADC1_CONVERSIONMODE_SINGLE, ADC1_CHANNEL_4, ADC1_PRESSEL_FCPU_D2,
 ADC1_EXTTRIG_TIM, ENABLE, ADC1_ALIGN_RIGHT, ADC1_SCHMITTTRIG_ALL,
 DISABLE);

It create a problem PC4 that prevously defined as a Timer channel.

I didn't define it as a ADC previously