104 lines
2.0 KiB
C
104 lines
2.0 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <linux/i2c-dev.h>
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#define PCF8591_ADDRESS 0x48
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int main(int argc, char **argv)
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{
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uint32_t fd;
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uint32_t ret;
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uint32_t adc_channel = 0;
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uint32_t dac_output = 0;
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uint8_t command[2] = {0};
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uint8_t value[4] = {0};
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useconds_t delay = 5000;
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char *dev = "/dev/i2c-0";
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printf("PCF8591 ADC and DAC test code\n");
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fd = open(dev, O_RDWR);
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if (fd < 0) {
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perror("Opening i2c device node\n");
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return -1;
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}
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ret = ioctl(fd, I2C_SLAVE, PCF8591_ADDRESS);
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if (ret < 0) {
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perror("Selecting i2c device\n");
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close (fd);
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return -1;
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}
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while (true) {
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printf("\n1. ADC 2. DAC 3. Exit\n");
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scanf("%d", &adc_channel);
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switch (adc_channel) {
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case 1:
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printf("\nEnter ADC channel number 0-3:\t");
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scanf("%d", &adc_channel);
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if ((adc_channel >= 0) && (adc_channel <= 3)) {
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/*
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* Analog output enable | Read Input i
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* See Page 6 of NXP PCF8591 data sheet
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*/
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command[0] = 0x40 | ((adc_channel) & 0x03); /* Control Byte */
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command[1] = dac_output; /* DAC Data Register */
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ret = write(fd, &command, 2);
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if (ret != 2) {
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perror("i2c write failed");
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continue;
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}
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usleep(delay);
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ret = read(fd, &value[0], 1);
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if(ret != 1) {
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perror("i2c read failed");
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continue;
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}
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printf("\nADC Channel %d: value: %d\n", adc_channel, value[0]);
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} else {
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printf("Invalid ADC channel number\n");
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}
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break;
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case 2:
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printf("Enter DAC value:\t");
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scanf("%d", &dac_output);
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command[0] = 0x40 | ((adc_channel) & 0x03); /* Control Byte */
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command[1] = dac_output & 0xff; /* DAC Data Register */
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ret = write(fd, &command, 2);
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if (ret != 2) {
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perror("i2c write failed");
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continue;
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}
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usleep(delay);
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break;
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case 3:
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goto exit;
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break;
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default:
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printf("Invalid input\n");
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break;
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}
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}
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exit:
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close(fd);
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return(0);
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}
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