Hi,
I wrote a very simple program which compare the analog reference input 0 (P0.00) with AIN0 (P0.26) and generate an interrupt on cross using Low Power comparator on nRF51822.
I watched the signals on the both P0.00 and P0.26, the P0.00 is stable at 1.6v and P0.26 is a sinusoidal wave form with average voltage of 1.6v and pick voltage of 1.7, i believe i have correct situation for getting cross interrupt and i assume in this case there is no problem with the hardware setup.
the program that i wrote is in the below
#include "boards.h"
#include <stdbool.h>
#include <stdint.h>
#include "nrf.h"
#include "nrf_delay.h"
#include "nrf_gpio.h"
void LPCOMP_init(void)
{
/* Enable interrupt on LPCOMP CROSS event */
NRF_LPCOMP->INTENSET = LPCOMP_INTENSET_CROSS_Msk;
NVIC_EnableIRQ(LPCOMP_IRQn);
/* Configure LPCOMP - P0.00*/
NRF_LPCOMP->REFSEL = (LPCOMP_REFSEL_REFSEL_ARef << LPCOMP_REFSEL_REFSEL_Pos);
NRF_LPCOMP->EXTREFSEL = (LPCOMP_EXTREFSEL_EXTREFSEL_AnalogReference0 << LPCOMP_EXTREFSEL_EXTREFSEL_Pos);
/* Configure LPCOMP - set reference input source to AIN pin 0, i.e. P0.26 */
NRF_LPCOMP->PSEL = (LPCOMP_PSEL_PSEL_AnalogInput0 << LPCOMP_PSEL_PSEL_Pos);
/* Enable and start the low power comparator */
NRF_LPCOMP->POWER = LPCOMP_POWER_POWER_Enabled;
NRF_LPCOMP->ENABLE = LPCOMP_ENABLE_ENABLE_Enabled;
NRF_LPCOMP->TASKS_START = 1;
}
/* Interrupt handler for LPCOMP */
void LPCOMP_IRQHandler(void)
{
// Clear event
NRF_LPCOMP->EVENTS_CROSS = 0;
// Sample the LPCOMP stores its state in the RESULT register.
// RESULT==0 means lower than reference voltage,
// RESULT==1 means higher than reference voltage
NRF_LPCOMP->TASKS_SAMPLE = 1;
// Toggle pin to indicate triggering of event
}
int main(void)
{
nrf_gpio_cfg_input(0,NRF_GPIO_PIN_NOPULL);
nrf_gpio_cfg_input(26,NRF_GPIO_PIN_NOPULL);
LPCOMP_init();
while(true)
{
//Put CPU to sleep while waiting for interrupt to save power
//__WFI();
}
}
I place a breakpoint in the interrupt handler but it never go into the interrupt function.
Please give me some suggestions.
