added initial avr/nano program

[ros_wild_thumper.git] / avr / nano / uart.c

diff --git a/avr/nano/uart.c b/avr/nano/uart.c
new file mode 100644 (file)
index 0000000..1a3707a
--- /dev/null
+++ b/avr/nano/uart.c
@@ -0,0 +1,97 @@
+#include <stdlib.h>
+#include "uart.h"
+#include <avr/interrupt.h>
+
+#define UART_UBRR_CALC(BAUD_,FREQ_) ((FREQ_)/((BAUD_)*16L)-1)
+
+static volatile        char read[RINGBUFFER_LEN];
+static volatile        char *in_read_ptr;
+static volatile        char *out_read_ptr;
+
+ISR(USART_RX_vect) {
+       // update read from uart
+       if (UCSR0A & (1<<RXC0)) {
+               *in_read_ptr = UDR0;
+
+               if (in_read_ptr < read + RINGBUFFER_LEN - 1) in_read_ptr++;
+               else in_read_ptr = (char *)read;
+       }
+}
+
+
+void setup_uart(unsigned int rate) {
+       UCSR0B |= (1<<TXEN0) | (1<<RXEN0); // UART TX & RX
+       UCSR0B |= (1<<RXCIE0);          // RX Interrupt
+       UCSR0C |= (3<<UCSZ00); // Asynchron 8N1
+
+       UBRR0H = (uint8_t)(UART_UBRR_CALC(rate, F_CPU) >> 8);
+       UBRR0L = (uint8_t)UART_UBRR_CALC(rate, F_CPU);
+
+       in_read_ptr = out_read_ptr = read;
+}
+
+
+void uart_putc(char *c) {
+       while (!(UCSR0A & (1<<UDRE0)));
+       UDR0 = *c;
+}
+
+
+int uart_putchar(char c, FILE *stream)
+{
+       uart_putc(&c);
+       return 0;
+}
+
+
+void uart_puts(char *s) {
+       char *c;
+
+       for (c = s; *c != '\0'; c++)
+               uart_putc(c);
+}
+
+
+int uart_getchar(FILE *stream)
+{
+       return uart_getc();
+}
+
+
+int uart_getc() {
+       while (!(UCSR0A & (1<<RXC0)));
+       return UDR0;
+}
+
+
+void uart_setup_stdout() {
+       fdevopen(uart_putchar, uart_getchar);
+}
+
+
+void uart_stream_update(ringbuffer_t *buffer) {
+       // update write to uart
+       if (buffer->out_write_ptr != buffer->in_write_ptr) {
+               if (UCSR0A & (1<<UDRE0)) {
+                       UDR0 = *buffer->out_write_ptr;
+                       if (buffer->out_write_ptr < buffer->write + RINGBUFFER_LEN - 1) buffer->out_write_ptr++;
+                       else buffer->out_write_ptr = buffer->write;
+               }
+       }
+
+       // update read from uart        
+       if (in_read_ptr != out_read_ptr) {
+               *buffer->in_read_ptr = *out_read_ptr;
+
+               // update newline chars
+               if (buffer->block_read == *buffer->in_read_ptr) buffer->newlines++;
+
+               if (buffer->in_read_ptr < buffer->read + RINGBUFFER_LEN - 1) buffer->in_read_ptr++;
+               else buffer->in_read_ptr = buffer->read;
+
+               // move pointer
+               if (out_read_ptr < read + RINGBUFFER_LEN - 1) out_read_ptr++;
+               else out_read_ptr = read;
+       }
+}
+