42/42_EXT_03_42chips
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

fix 8 bit precision in ex00 and ex01

Browse Source
This commit is contained in:
hugogogo
2025-03-15 14:42:03 +01:00
parent 5904f7c5e0
commit e9e3cd09dd
3 changed files with 8 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
module05/ex00/adc.c
View File

@@ -12,6 +12,7 @@
void adc_init(uint8_t prescaler_value) {
ADMUX = (1 << REFS0); // Table 24-3 : set voltage reference, AVCC with external capacitor at AREF pin
ADMUX |= (1 << ADLAR); // 24.9.1 : result is left adjusted, meaning the first 8 bits values are readable in ADCH, (24.9.3.2 : ADC data register is not updated util ADCH is read)
ADCSRA = (1 << ADEN); // 24.9.2 : enable ADC
ADCSRA |= (1 << ADATE); // 24.9.2 : enable Auto Trigger -> it will start a conversion on the selected channel in ADMUX when the selected source (in ADCSRB) is triggered
ADCSRA |= (1 << ADIE); // 24.9.2 : enable ADC Interrupt
@@ -29,6 +30,6 @@ void adc_print_hex(uint8_t value) {
}
ISR(ADC_vect) { // Table 12-6 : interrupt vector for ADC Conversion Complete
uint16_t value = ADC;
uint8_t value = ADCH; // 24.9.3.2 : read ADCH 8 bits precision
adc_print_hex(value);
}

8
module05/ex01/adc.c
View File

@@ -4,6 +4,7 @@
void adc_init(uint8_t prescaler_value) {
ADMUX = (1 << REFS0); // Table 24-3 : set voltage reference, AVCC with external capacitor at AREF pin
ADMUX |= (1 << ADLAR); // 24.9.1 : result is left adjusted, meaning the first 8 bits values are readable in ADCH, (24.9.3.2 : ADC data register is not updated util ADCH is read)
ADCSRA = (1 << ADEN); // 24.9.2 : enable ADC
ADCSRA |= (1 << ADATE); // 24.9.2 : enable Auto Trigger -> it will start a conversion on the selected channel in ADMUX when the selected source (in ADCSRB) is triggered
ADCSRA |= (1 << ADIE); // 24.9.2 : enable ADC Interrupt
@@ -13,7 +14,6 @@ void adc_init(uint8_t prescaler_value) {
ADMUX = (ADMUX & 0b11110000) | (adc_channel & 0b1111); // Table 24-4 : Select ADC channel 0
}
void adc_print_hex(uint8_t value) {
char buffer[3] = {0};
int_to_hex_string(value, buffer, 2);
@@ -21,10 +21,12 @@ void adc_print_hex(uint8_t value) {
}
ISR(ADC_vect) { // Table 12-6 : interrupt vector for ADC Conversion Complete
uint16_t value = ADC;
uint8_t value = ADCH; // 24.9.3.2 : read ADCH 8 bits precision
adc_print_hex(value);
// loop through channel
adc_channel = (adc_channel + 1) % 3; // loop through channels
ADMUX = (ADMUX & 0b11110000) | (adc_channel & 0b1111); // Table 24-4 : Select ADC channel
ADMUX = (ADMUX & 0b11110000) | (adc_channel & 0b1111); // Table 24-4 : Select next ADC channel
if (adc_channel != 0) {
uart_printstr(", ");
ADCSRA |= (1 << ADSC); // 24.9.2 : start next conversion

2
module05/ex01/main.c
View File

@@ -16,7 +16,7 @@
volatile uint8_t adc_channel = 0; // Table 14-6 : alternate function for RV1 on PC0 -> ADC0, LDR on PC1 -> ADC1, NTC on PC2 -> ADC2 ...
// read 3 analog values and print them in uart as hexadecimal 2-number : potentiometer RV1 (Variable Resistor), photoresistor LDR (Light Dependent Resistor), thermistor NTC (Negative Temperature Coefficient)
// read 3 analog values at 8 bits and print them in uart as hexadecimal 2-number : potentiometer RV1 (Variable Resistor), photoresistor LDR (Light Dependent Resistor), thermistor NTC (Negative Temperature Coefficient)
int main() {
char buffer[4];
SREG |= ENABLE_GLOBAL_INTERRUPT; // 7.3.1 : Status Register, bit 7 : I – Global Interrupt Enable