Using ADC interrupts in RTOS environment. This program also demonstrates the usage of RTOS API function calls from interrupt.
main.cpp
- Committer:
- cspista
- Date:
- 2022-04-10
- Revision:
- 0:b6055a7af0c9
File content as of revision 0:b6055a7af0c9:
#include "mbed.h" #include "rtos.h" AnalogIn adc(A4); DigitalOut led1(LED1); typedef uint32_t message_t; Queue <message_t, 4> queue; void led1_thread(void const *args) { while (true) { led1 = !led1; Thread::wait(1000); } } //--- ADC Interrupt handler ----------------- extern "C" void ADC1_IRQHandler() { NVIC_ClearPendingIRQ(ADC_IRQn); //Clear ADC Interrupt Request Flag uint16_t raw = ADC1->DR; queue.put((message_t*)raw); //Send result through a Queue } //--- Start conversion, wait for result ----- uint16_t adc_read(uint32_t ch) { ADC1->SQR3 = ch; //set conversion channel ADC1->SMPR2 = 7; //Sample time =480 ADC1->CR1 |= ADC_CR1_EOCIE; //enable interrupt ADC1->CR2 |= ADC_CR2_SWSTART; //Start conversion osEvent evt = queue.get(); //Wait for a message return (uint16_t)evt.value.v; //Return obtained value } int main() { int32_t v25 = 760; //Voltage at 25C (in millivolts) float m = 2.5; //Slope mV per degree) uint16_t dummy = adc.read(); //needed for ADC configuration ADC123_COMMON->CCR |= ADC_CCR_TSVREFE; //Enable inner channels NVIC_SetVector(ADC_IRQn,(uint32_t)&ADC1_IRQHandler); //Attach ADC ISR NVIC_EnableIRQ(ADC_IRQn); //Enable ADC interrupts Thread thread1(led1_thread); printf("\r\n Lab09 ADC interrupt in RTOS environment\r\n"); while(true) { uint32_t a1 = 0; uint32_t a2 = 0; for(int i=0; i<3300; i++) { a1 += adc_read(11); //Measure voltage at A4 (PTC_1) a2 += adc_read(18); //Internal temperature sensor } float v1 = a1/4096.0f; //Convert v1 to millivolts float temp1 = (v1-500)/10.0; //MCP9700 temperature in Celsius float v2 = a2/4096.0f; //Convert v2 to millivolts float temp2 = 25.0f+(v2-v25)/m; //Calculate temp in Celsius printf("A4 = %.0f mV Temp = %.1f C Inner Ts: %.0f mV Temp = %.1f C\r\n",v1,temp1,v2,temp2); Thread::wait(2000); } }