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About HW-Trigger ADC

Question asked by Ray Xie on Jan 12, 2018

I configure a hardware trigger for ADC0 with FTM2_INIT_TRIG -> PDB0_trigger_in0(back to back) ->  ADC0.

 

Here is ADC channel info:
ADC0->SC1[0] = ADC_SC1_ADCH(ADC0SE15);
ADC0->SC1[1] = ADC_SC1_ADCH(ADC0SE8); 
ADC0->SC1[2] = ADC_SC1_ADCH(ADC0SE9);
ADC0->SC1[3] = ADC_SC1_ADCH(ADC0SE14); 
ADC0->SC1[4] = ADC_SC1_ADCH(ADC0SE11);
ADC0->SC1[5] = ADC_SC1_AIEN_MASK|ADC_SC1_ADCH(ADC0SE6); 

 

TRGMUX configuration:

TRGMUX->TRGMUXn[TRGMUX_PDB0_INDEX] = TRGMUX_TRGMUXn_SEL0(TRGMUX_TRIG_SOURCE_FTM2_INIT_TRIG);

 

TRGMUX configuration:

PDB0->CH[0].C1 = PDB_C1_BB(0x3E) | /* back-to-back enable: 0b0011 1110 */
                              PDB_C1_TOS(1) | /* Pretrigger Output Select: 0=bypassed , 1=enabled */
                              PDB_C1_EN(0x3F); /* PDB channel's [3:0] pre-trigger enabled */

 

And I find there are some strange pulses on ADC0SE15 (PTC17/ADC0_SE15/FTM1_FLT3) pin.

Anybody knowes why there are pulses?

 

The MCU is s32k144 with 64 pins.


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