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

wip ex01

Browse Source
This commit is contained in:
hugo LAMY
2025-03-07 09:09:16 +01:00
parent 936c591be4
commit 10480f63d7
1 changed files with 34 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
module02/ex01/main.c
View File

@@ -2,8 +2,8 @@
#include <util/delay.h>
#include <avr/interrupt.h>
// mathematics
#define DIV_ROUND_CLOSEST(n, d) ((((n) < 0) == ((d) < 0)) ? (((n) + (d)/2)/(d)) : (((n) - (d)/2)/(d)))
// mathematics
#define DIV_ROUND_CLOSEST(n, d) ((((n) < 0) == ((d) < 0)) ? (((n) + (d)/2)/(d)) : (((n) - (d)/2)/(d))) // https://stackoverflow.com/a/18067292
// stringify
#define STRINGIFY_HELPER(x) #x
@@ -86,10 +86,20 @@
#define TRANSMITTER_DISABLED (0<<TXEN0)
#define TRANSMITTER_ENABLED (1<<TXEN0)
// TIMER
#define PERIOD 2000
// Table 16-4 : Waveform Generation Mode Bit Description
#define CTC_TOP_OCR1A_IN_TCCR1B (0<<WGM13 | 1<<WGM12)
#define CTC_TOP_OCR1A_IN_TCCR1A (0<<WGM11 | 0<<WGM10)
#define CTC_TOP_ICR1_IN_TCCR1B (1<<WGM13 | 1<<WGM12)
#define CTC_TOP_ICR1_IN_TCCR1A (0<<WGM11 | 0<<WGM10)
#define FAST_PWM_TOP_OCR1A_IN_TCCR1B (1<<WGM13 | 1<<WGM12)
#define FAST_PWM_TOP_OCR1A_IN_TCCR1A (1<<WGM11 | 1<<WGM10)
#define FAST_PWM_TOP_ICR1_IN_TCCR1B (1<<WGM13 | 1<<WGM12)
#define FAST_PWM_TOP_ICR1_IN_TCCR1A (1<<WGM11 | 0<<WGM10)
// END MACROS
// 20.4 Frame Formats : 8N1 : 8 data bits, no parity, 1 stop bit
// 20.5 USART Initialization : (1) setting baud rate, (2) setting frame format, (3) enabling the Transmitter or the Receiver
void uart_init() {
UBRR0H = (unsigned char) (BAUD_PRESCALER >> 8); // 20.11.5 : UBRRnL and UBRRnH – USART Baud Rate Registers
UBRR0L = (unsigned char) BAUD_PRESCALER;
@@ -104,10 +114,25 @@ void uart_tx(char c) {
UDR0 = (unsigned char) c; // 20.11.1 : Put data into buffer, UDRn – USART I/O Data Register (read and write)
}
int main() {
uart_init();
while (1) {
uart_tx('Z');
_delay_ms(1000);
void uart_printstr(const char* str) {
while (*str) {
uart_tx(*str);
str++;
}
}
// print hello world, on serial port, every 2 seconds, with empty infinite loop
int main() {
uart_init();
TCCR1A |= CTC_TOP_OCR1A_IN_TCCR1A; // Table 16-4 : set timer in CTC (Clear Time on Compare) mode
TCCR1B |= CTC_TOP_OCR1A_IN_TCCR1B;
TCCR1A |= (1 << COM1A0); // 14.3.1 : set Compare Output with COM1A0, it toggles OC1A on compare match (Table 16-1), OC1A is alternate function for PORTB1 (Table 14-3)
OCR1A = TIME_MS(PERIOD); // Table 16-4 : set CTC compare value, the counter is cleared to zero when the counter value (TCNT1) matches the OCR1A register
TCCR1B |= (PRESCALE_SET);
while(1);
}