topic Re: ADC Hardware Trigger in S32K

ADC Hardware Trigger

akhilranga — Tue, 16 Aug 2022 09:31:46 GMT

Hello Community.

The below is the example code for ADC in #S32k144#, In that "convertAdcChan(12);" this command is used to convert AD12 to potentiometer on EVB. i am trying to convert that to an external Temperature sesnor LM35 instead of onboard Potentiometer. so i am asuming i can use one ADC function pin such as PTC1 , PTC2 use as data pin for LM35 . But how can i interface that with this code. Like the potentiometer pin is PTC14. But i dont see anywhere it being called or defined in this code. But how did Potentiometer got activated.

My understanding is if i replace on board potentiometer with LM35 things should work.

Help required for : how can i interface my LM35 with 3 pins (VCC, DATA, GND) by leveraging this code.

Please let me know if i am wrong and help me out.

#include "S32K144.h" /* include peripheral declarations S32K144 */ #include "clocks_and_modes.h" #include "ADC.h" #define PTD15 15 /* RED LED*/ #define PTD16 16 /* GREEN LED*/ #define PTD0 0 /* BLUE LED */ void PORT_init (void) { PCC->PCCn[PCC_PORTD_INDEX ]|=PCC_PCCn_CGC_MASK; /* Enable clock for PORTD */ PORTD->PCR[PTD0] = 0x00000100; /* Port D0: MUX = GPIO */ PORTD->PCR[PTD15] = 0x00000100; /* Port D15: MUX = GPIO */ PORTD->PCR[PTD16] = 0x00000100; /* Port D16: MUX = GPIO */ PTD->PDDR |= 1<<PTD0; /* Port D0: Data Direction= output */ PTD->PDDR |= 1<<PTD15; /* Port D15: Data Direction= output */ PTD->PDDR |= 1<<PTD16; /* Port D16: Data Direction= output */ } void WDOG_disable (void){ WDOG->CNT=0xD928C520; /* Unlock watchdog */ WDOG->TOVAL=0x0000FFFF; /* Maximum timeout value */ WDOG->CS = 0x00002100; /* Disable watchdog */ } int main(void) { uint32_t adcResultInMv=0; WDOG_disable(); /* Disable WDOG*/ SOSC_init_8MHz(); /* Initialize system oscillator for 8 MHz xtal */ SPLL_init_160MHz(); /* Initialize SPLL to 160 MHz with 8 MHz SOSC */ NormalRUNmode_80MHz(); /* Init clocks: 80 MHz sysclk & core, 40 MHz bus, 20 MHz flash */ PORT_init(); /* Init port clocks and gpio outputs */ ADC_init(); /* Init ADC resolution 12 bit*/ for(;;) { convertAdcChan(12); /* Convert Channel AD12 to pot on EVB */ while(adc_complete()==0){} /* Wait for conversion complete flag */ adcResultInMv = read_adc_chx(); /* Get channel's conversion results in mv */ if (adcResultInMv > 3750) { /* If result > 3.75V */ PTD->PSOR |= 1<<PTD0 | 1<<PTD16; /* turn off blue, green LEDs */ PTD->PCOR |= 1<<PTD15; /* turn on red LED */ } else if (adcResultInMv > 2500) { /* If result > 2.5V */ PTD->PSOR |= 1<<PTD0 | 1<<PTD15; /* turn off blue, red LEDs */ PTD->PCOR |= 1<<PTD16; /* turn on green LED */ } else if (adcResultInMv >1250) { /* If result > 1.25V */ PTD->PSOR |= 1<<PTD15 | 1<<PTD16; /* turn off red, green LEDs */ PTD->PCOR |= 1<<PTD0; /* turn on blue LED */ } else { PTD->PSOR |= 1<<PTD0 | 1<< PTD15 | 1<<PTD16; /* Turn off all LEDs */ } convertAdcChan(29); /* Convert chan 29, Vrefsh */ while(adc_complete()==0){} /* Wait for conversion complete flag */ adcResultInMv = read_adc_chx(); /* Get channel's conversion results in mv */ } }

Thanks

Re: ADC Hardware Trigger

PetrS — Tue, 16 Aug 2022 12:46:38 GMT

Hi,

if you connect DATA pin of sensor to e.g PTC1 then you need to convert external channel 9 on the ADC

So within this code it should be enough to use

convertAdcChan(9); /* Convert Channel AD9, PTC1 on EVB */

BR, Petr

Re: ADC Hardware Trigger

akhilranga — Wed, 17 Aug 2022 06:50:39 GMT

Hi @PetrS

Thanks for the help i got it. I was missing that link between ADC channel and port pins. Thanks again for the help.

Now i just wanted to understand one last thing. I am trying to input 5v input to the sesnor. So, how can i do that. I noticed VDD pins but plese let me know how i can initiate that with this code. I am assuming inorder to access the VDD pins as 5v Power supply, i need to enable clocks and initiate the pins.

P.S : i just statrted exploring this S32k144 . Excuse my naivety.

Thanks for the help

Re: ADC Hardware Trigger

PetrS — Wed, 17 Aug 2022 12:30:01 GMT

Hi,

not sure what you meant. If sensor has 3 wires (VCC, DATA, GND) connect DATA to PTC1 and VCC/GND to VDD/GND, see EVB schematic, VDD/GND and PTC1 are on J5 header.

BR, Petr

Re: ADC Hardware Trigger

akhilranga — Thu, 18 Aug 2022 06:52:55 GMT

Hi @PetrS

Yes. I am planning to do the same . But my question was related to VDD pin. Do i need to interface it the same way i will interface the PTC1

Like, do i need to enable clock or something.

Re: ADC Hardware Trigger

PetrS — Mon, 22 Aug 2022 07:09:56 GMT

Hi,

VDD is just power pin, no setting is for that, you need to connect external voltage to VDD to power the MCU.

BR, Petr

Re: ADC Hardware Trigger

akhilranga — Mon, 22 Aug 2022 12:06:26 GMT

Hi @PetrS .

Thanks for the asssist. Got that thing figured out.