diff --git a/module05/ex02/Makefile b/module05/ex02/Makefile new file mode 100644 index 0000000..2e40cba --- /dev/null +++ b/module05/ex02/Makefile @@ -0,0 +1 @@ +include ../../Makefile \ No newline at end of file diff --git a/module05/ex02/adc.c b/module05/ex02/adc.c new file mode 100644 index 0000000..9022c6a --- /dev/null +++ b/module05/ex02/adc.c @@ -0,0 +1,47 @@ +#include "header.h" + +// 24.2 : The ADC generates a 10-bit result which is presented in the ADC Data Registers, ADCH and ADCL + +void adc_init(uint8_t prescaler_value) { + ADMUX = (1 << REFS0); // Table 24-3 : set voltage reference, AVCC with external capacitor at AREF pin + 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 + ADCSRA |= ADC_PRESCALE_SET(prescaler_value); // Table 24-5 : prescaler ADC + + ADCSRB = ADC_TRIGGER_TIMER_1_COMPARE_B; // Table 24-6 : ADC Auto Trigger Source + ADMUX = (ADMUX & 0b11110000) | (adc_channel & 0b1111); // Table 24-4 : Select ADC channel 0 +} + +void adc_print_dec(uint16_t value) { + char buffer[17] = {0}; + + // handle zero case + if (value == 0) { + buffer[15] = '0'; + uart_printstr(&buffer[15]); + return; + } + + uint8_t pos = 0; + while (value) { + uint8_t digit = value % 10; + buffer[15 - pos] = digit + '0'; + value /= 10; + pos++; + } + uart_printstr(&buffer[16 - pos]); // send only from first digit +} + +ISR(ADC_vect) { // Table 12-6 : interrupt vector for ADC Conversion Complete + uint16_t value = ADC; // 24.9.3.2 : read ADC 16 bits precision + adc_print_dec(value); + adc_channel = (adc_channel + 1) % 3; // loop through channels + ADMUX = (ADMUX & 0b11110000) | (adc_channel & 0b1111); // Table 24-4 : Select ADC channel + if (adc_channel != 0) { + uart_printstr(", "); + ADCSRA |= (1 << ADSC); // 24.9.2 : start next conversion + } else { + uart_printstr("\r\n"); + } +} diff --git a/module05/ex02/header.h b/module05/ex02/header.h new file mode 100644 index 0000000..810b00f --- /dev/null +++ b/module05/ex02/header.h @@ -0,0 +1,41 @@ +#ifndef HEADER_H +#define HEADER_H + +#include +#include +#include + +#include "utils.h" +#include "bitmanip.h" +#include "interrupt.h" +#include "timer.h" +#include "usart.h" +#include "adc.h" + +// +// GLOBAL +// +extern volatile uint8_t adc_channel; + +// +// PROTOTYPES +// +// main.c +// timer.c +void timer_1B_init(); +// math.c +void int_to_hex_string(uint64_t value, char *out, uint8_t num_digits); +// adc.c +void adc_init(uint8_t prescaler_value); +uint16_t adc_read(uint8_t channel); +// uart.c +void uart_init(); +void uart_tx(char c); +void uart_printstr(const char* str); +void uart_printstr_endl(const char* str); + +// +// MACROS +// + +#endif // HEADER_H \ No newline at end of file diff --git a/module05/ex02/main.c b/module05/ex02/main.c new file mode 100644 index 0000000..c8eab02 --- /dev/null +++ b/module05/ex02/main.c @@ -0,0 +1,29 @@ +#include "header.h" + +// 1.1.7 : AVCC is the supply voltage pin for the A/D Converter, PC3:0, and ADC7:6 +// 1.1.8 : AREF is the analog reference pin for the A/D Converter +// 24.4 : frequency needs to be between 50kHz and 200kHz, for less than 10bits accuracy it can be >200kHz +// -> Frequence_ADC = Frequance_CPU / Prescaler (Fadc = Fcpu/P): +// - P = 2 -> Fadc = 16,000,000 / 2 = 8,000,000 = 8MHz +// - P = 4 -> Fadc = 16,000,000 / 4 = 4,000,000 = 4MHz +// - P = 8 -> Fadc = 16,000,000 / 8 = 2,000,000 = 2MHz +// - P = 16 -> Fadc = 16,000,000 / 16 = 1,000,000 = 1MHz +// - P = 32 -> Fadc = 16,000,000 / 32 = 500,000 = 500KHz +// - P = 64 -> Fadc = 16,000,000 / 64 = 250,000 = 250KHz -> OK +// - P = 128 -> Fadc = 16,000,000 / 128 = 125,000 = 125KHz -> OK + +#define ADC_PRESCALER 128 // Table 24-5 : can only be 2, 4, 8, 16, 32, 64, or 128 + +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 at 10 bits and print them in uart as decimal : 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 + uart_init(); + adc_init(ADC_PRESCALER); + + timer_1B_init(); + + while(1); +} diff --git a/module05/ex02/math.c b/module05/ex02/math.c new file mode 100644 index 0000000..1f61877 --- /dev/null +++ b/module05/ex02/math.c @@ -0,0 +1,9 @@ +#include "header.h" + +void int_to_hex_string(uint64_t value, char *out, uint8_t num_digits) { // num_digits : number of digit of the output, ex 2 for 3FF (1023) -> FF + for (uint8_t i = 0; i < num_digits; ++i) { + uint8_t shift = (num_digits - 1 - i) * 4; + out[i] = INT_TO_HEX_CHAR((value >> shift) & 0x0F); + } + out[num_digits] = '\0'; +} diff --git a/module05/ex02/timer.c b/module05/ex02/timer.c new file mode 100644 index 0000000..0be9c38 --- /dev/null +++ b/module05/ex02/timer.c @@ -0,0 +1,22 @@ +#include "header.h" + +// Set up Timer1 in CTC mode to trigger every 20ms +// With 16MHz clock and prescaler of 64, and OCR1A = 49999: +// 16000000/64/50000 = 20ms period + +#define T1B_PRESCALE_VALUE 64 + +void timer_1B_init() { + TCCR1A = 0; // 16.11.1 : Normal operation, OC1A/OC1B disconnected + TCCR1B = CTC_TOP_OCR1A_IN_TCCR1B; // 16.11.2 : CTC mode top OCR1A + TCCR1B |= T1_PRESCALE_SET(T1B_PRESCALE_VALUE); // 16.11.2 : prescaler + + OCR1A = TIME_MS(20, T1B_PRESCALE_VALUE); // 16.11.5 : Compare match value for register A + OCR1B = 0; // 16.11.6 : Compare match value for register B, if not defined, should default to 0 + + TIMSK1 = (1 << OCIE1B); // 16.11.8 : Enable Timer1 Compare B Match Interrupt +} + +ISR(TIMER1_COMPB_vect) { + // Empty ISR to ensure proper flag clearing or something like that (p145 : "OCF1B is automatically cleared when the Output Compare Match B Interrupt Vector is executed") +} \ No newline at end of file diff --git a/module05/ex02/uart.c b/module05/ex02/uart.c new file mode 100644 index 0000000..f0231f0 --- /dev/null +++ b/module05/ex02/uart.c @@ -0,0 +1,77 @@ +#include "header.h" + +// MACROS +// USART +#define USART_BAUDRATE 115200 +#define INPUT_SIZE 7 + +// GLOBAL VARIABLES + +// +// FUNCTIONS +// +void uart_init() { + UBRR0H = (unsigned char) (BAUD_PRESCALER(USART_BAUDRATE) >> 8); // 20.11.5 : UBRRnL and UBRRnH – USART Baud Rate Registers + UBRR0L = (unsigned char) BAUD_PRESCALER(USART_BAUDRATE); + UCSR0C = DATA_EIGHT_BIT; // 20.11.4 : set Frame Format + UCSR0B = TRANSMITTER_ENABLED; // 20.11.3 : enable Receiver, Transmitter, and interrupts +} + +// char uart_rx(void) { +// while (!TEST(UCSR0A, RXC0)); // 20.11.2 : do nothing until there are unread data in the receive buffer (UDRn), (RXCn flag in UCSRnA register set to 1 when buffer has data) +// return UDR0; // 20.11.1 : get data in buffer, UDRn – USART I/O Data Register (read and write) +// } + +void uart_tx(char c) { + while (!TEST(UCSR0A, UDRE0)); // 20.11.2 : do nothing until UDRn buffer is empty, (UDREn flag in UCSRnA register set to 1 when buffer empty) + UDR0 = (unsigned char) c; // 20.11.1 : Put data into buffer, UDRn – USART I/O Data Register (read and write) +} + +void uart_printstr(const char* str) { + while (*str) { + uart_tx(*str); + str++; + } +} + +void uart_printstr_endl(const char* str) { + uart_printstr(str); + uart_printstr("\r\n"); +} + +// ISR(USART_RX_vect) { // Table 12-6 : we select the code for USART Receive +// char received_char = UDR0; // read received character +// if (received_char == '\b' || received_char == 127) { // if backspace is received +// if (input_index <= 0) { +// return; +// } +// if (input_index >= INPUT_SIZE) { +// return; +// } +// remove_last_character(); +// input_index--; +// uart_tx('\b'); // Move cursor back +// uart_tx(' '); // Erase the character on screen +// uart_tx('\b'); // Move cursor back again +// } else if (received_char == '\n' || received_char == '\r') { // if enter is received +// if (input_index != INPUT_SIZE) { +// return; +// } +// set_color((char *)color_input); +// reset_input(); +// } else { // any other character +// if (input_index >= INPUT_SIZE) { +// return; +// } +// if (!is_valid_color_input(received_char)) { +// return; +// } +// fill_str(received_char); +// uart_tx(received_char); +// input_index++; +// } +// } + +// ISR(USART_TX_vect) { // Table 12-6 : we select the code for USART Transmit +// char received_char = UDR0; // read received character +// }