backspace works

This commit is contained in:
hugogogo
2025-03-07 17:58:11 +01:00
parent 3140b1a491
commit 91788897b1
3 changed files with 29 additions and 22 deletions

View File

@@ -104,7 +104,8 @@ 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)
}
// screen /dev/ttyUSB0 115200
// write Z on serial port, at a !Hz frequency
// `screen /dev/ttyUSB0 115200`
int main() {
uart_init();
while (1) {

View File

@@ -62,29 +62,29 @@
// USART
// Table 20-1 : Baud Rate Calculation
#define USART_BAUDRATE 115200
#define BAUD_PRESCALER (DIV_ROUND_CLOSEST(F_CPU, (16 * USART_BAUDRATE)) - 1)
#define USART_BAUDRATE 115200
#define BAUD_PRESCALER (DIV_ROUND_CLOSEST(F_CPU, (16 * USART_BAUDRATE)) - 1)
// Table 20-8 : Mode Selection (USART Mode SELect)
#define ASYNCHRONOUS (0<<UMSEL01 | 0<<UMSEL00)
#define SYNCHRONOUS (0<<UMSEL01 | 1<<UMSEL00)
#define ASYNCHRONOUS (0<<UMSEL01 | 0<<UMSEL00)
#define SYNCHRONOUS (0<<UMSEL01 | 1<<UMSEL00)
// Table 20-9 : Parity Bit Selection (USART Parity Mode)
#define PARITY_DISABLED (0<<UPM01 | 0<<UPM00)
#define PARITY_EVEN (1<<UPM01 | 0<<UPM00)
#define PARITY_ODD (1<<UPM01 | 1<<UPM00)
#define PARITY_DISABLED (0<<UPM01 | 0<<UPM00)
#define PARITY_EVEN (1<<UPM01 | 0<<UPM00)
#define PARITY_ODD (1<<UPM01 | 1<<UPM00)
// Table 20-10 : Stop Bit Selection (USART Stop Bit Select)
#define STOP_ONE_BIT (0<<USBS0)
#define STOP_TWO_BIT (1<<USBS0)
#define STOP_ONE_BIT (0<<USBS0)
#define STOP_TWO_BIT (1<<USBS0)
// Table 20-11 : Data Bit Selection (USART Character SiZe)
#define DATA_FIVE_BIT (0<<UCSZ02 | 0<<UCSZ01 | 0<<UCSZ00)
#define DATA_SIX_BIT (0<<UCSZ02 | 0<<UCSZ01 | 1<<UCSZ00)
#define DATA_SEVEN_BIT (0<<UCSZ02 | 1<<UCSZ01 | 0<<UCSZ00)
#define DATA_EIGHT_BIT (0<<UCSZ02 | 1<<UCSZ01 | 1<<UCSZ00)
#define DATA_NINE_BIT (1<<UCSZ02 | 1<<UCSZ01 | 1<<UCSZ00)
#define DATA_FIVE_BIT (0<<UCSZ02 | 0<<UCSZ01 | 0<<UCSZ00)
#define DATA_SIX_BIT (0<<UCSZ02 | 0<<UCSZ01 | 1<<UCSZ00)
#define DATA_SEVEN_BIT (0<<UCSZ02 | 1<<UCSZ01 | 0<<UCSZ00)
#define DATA_EIGHT_BIT (0<<UCSZ02 | 1<<UCSZ01 | 1<<UCSZ00)
#define DATA_NINE_BIT (1<<UCSZ02 | 1<<UCSZ01 | 1<<UCSZ00)
// 20.11.3 : USART Control and Status Register B (UCSRnB)
#define RECEIVER_DISABLED (0<<RXEN0)
#define RECEIVER_ENABLED (1<<RXEN0)
#define TRANSMITTER_DISABLED (0<<TXEN0)
#define TRANSMITTER_ENABLED (1<<TXEN0)
#define RECEIVER_DISABLED (0<<RXEN0)
#define RECEIVER_ENABLED (1<<RXEN0)
#define TRANSMITTER_DISABLED (0<<TXEN0)
#define TRANSMITTER_ENABLED (1<<TXEN0)
// TIMER
#define PERIOD 2000
@@ -134,7 +134,7 @@ void uart_printstr(const char* str) {
}
}
// print hello world, on serial port, every 2 seconds, with empty infinite loop
// print "Hello World!\n", on serial port, every 2 seconds, with empty infinite loop
// `screen /dev/ttyUSB0 115200`
int main() {
uart_init();
@@ -154,5 +154,5 @@ int main() {
// ISR interrupt macro : https://www.nongnu.org/avr-libc/user-manual/group__avr__interrupts.html
ISR(TIMER1_COMPA_vect) { // Table 12-7 : we select the code for timer 1 on channel A
uart_printstr("Hello World!");
uart_printstr("Hello World!\r\n"); // \n and \r : https://stackoverflow.com/questions/7812142/how-to-toggle-cr-lf-in-gnu-screen
}

View File

@@ -142,7 +142,13 @@ void uart_tx(char c) {
ISR(USART_RX_vect) { // Table 12-7 : we select the code for USART Receive
// char received_char = uart_rx();
char received_char = UDR0; // Read received character
uart_tx(SWITCH_CASE(received_char)); // Toggle case and send back
if (received_char == '\b' || received_char == 127) { // If backspace is received
uart_tx('\b'); // Move cursor back
uart_tx(' '); // Erase the character on screen
uart_tx('\b'); // Move cursor back again
} else {
uart_tx(SWITCH_CASE(received_char)); // Toggle case and send back
}
}
// send back caracters received on serial port with case toggling, using interupt and empty infinite loop