avjarun
Joined: 28 Mar 2021
Posts: 13
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| DAC - COMPARATOR HELP |
 Posted: Tue Jul 08, 2025 6:34 am |
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Hello all.
I am trying to trigger an Interrupt using comparator, but struggling with the code as the interrupt never triggers.
Have an ADC INPUT on RA2 - Connected to Analog Hall Effect Sensor that varies between analog value 132 to 135 and I would like have that as an interrupt.
Can someone advice if what I think can be implemented and if yes, where am I am wrong. Pls point me in the right direction.
| Code: |
#include <16F18325.h>
#include <stdio.h>
#fuses RSTOSC_HFINTRC_PLL,NOBROWNOUT,NOWDT,MCLR,PUT
#use delay(clock=32000000)
#use i2c(Master, SDA=PIN_C0, SCL=PIN_C1, slow=100000, FORCE_SW, stream=SSD1306_STREAM)
#define SSD1306_ADDRESS 0x78
#define SSD1306_128_32
#include <SSD1306OLED.c>
unsigned long pulse_count = 0;
unsigned long counter = 0;
unsigned long lcounter = 0;
#bit C1OUT = getenv("SFR:CM1CON0").6 // Comparator 1 output
#byte PORTA = 0x00C
#byte PORTC = 0x00E
#bit LED = PORTA.5
#bit LEDACT = PORTA.4
#bit EON=PORTC.2
char text[10];
byte adcValue;
int previous_state = 0; // 0 = below threshold, 1 = above
int16 threshold = 133;
#INT_COMP
void comp_isr() {
LEDACT=!LEDACT;
if (C1OUT) {
counter++;
LED = !LED;
}
}
void ssd1306_init() {
// Initialize SSD1306 for 128x32 display
SSD1306_Begin(SSD1306_SWITCHCAPVCC, SSD1306_ADDRESS);
SSD1306_Display(); // Update display
}
void showCounter(){
sprintf(text, "%06lu", counter); // Format as 5 digits
SSD1306_DrawText(26, 10, text, 2);
SSD1306_Display();
}
void main() {
set_tris_a(0b001100);
set_tris_c(0b001011);
setup_adc_ports(NO_ANALOGS);
EON=1;
LED = 1;
LEDACT=0;
delay_ms(1000);
ssd1306_init(); // Initialize OLED
ssd1306_ClearDisplay(); // Clear screen
showCounter();
LED = 0;
setup_dac(DAC_VSS_VDD);
dac_write(132); // DAC as reference
setup_adc_ports(sAN2);
setup_comparator(CP1_C3_DAC | CP1_INT_L2H | CP1_HYST);
clear_interrupt(INT_COMP);
enable_interrupts(INT_COMP);
enable_interrupts(PERIPH);
enable_interrupts(GLOBAL);
while (TRUE) {
if (lcounter != counter) {
showCounter();
lcounter = counter;
}
}
} |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19967
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| Posted: Tue Jul 08, 2025 7:12 am |
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Key thing. the DAC only offers 32 levels. 0-31. These have 1/32 the supply
for each step. You don't tell us what '132' to '135' 'represents?. Counts of
the ADC?. In 8 bit or 10 bit mode if so?.
However this would be in DAC counts:
For 8bit adc, 16 counts.
For 10 bit, just 4 counts.
and of course the variation would have to be a lot more than just 3 ADC counts
for this to be even remotely useable.....
Look at figure 24-1 in the dats sheet. |
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