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-rw-r--r--sw/programmer/avr/usart.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/sw/programmer/avr/usart.c b/sw/programmer/avr/usart.c
new file mode 100644
index 0000000..8c2eb38
--- /dev/null
+++ b/sw/programmer/avr/usart.c
@@ -0,0 +1,107 @@
+#include "usart.h"
+
+static uint16_t usart_baudrate;
+static uint16_t usart_baud_prescale;
+
+void usart_init(uint16_t baudrate)
+{
+ // enable RX and TX
+ UCSR0B |= _BV(RXEN0) | _BV(TXEN0);
+
+ // set 8 bit size char
+ UCSR0C |= _BV(UCSZ01) | _BV(UCSZ00);
+
+ // set baudrate
+ usart_baudrate = baudrate;
+ usart_baud_prescale = (F_CPU / (usart_baudrate * 16)) -1;
+
+ UBRR0L = usart_baud_prescale;
+ UBRR0H = usart_baud_prescale >> 8;
+}
+
+void usart_send_byte(uint8_t data)
+{
+ while (!(UCSR0A & _BV(UDRE0)));
+ UDR0 = data;
+}
+
+void usart_send(uint8_t *data, size_t len)
+{
+ uint8_t *p = data;
+
+ while (len--) {
+ usart_send_byte(*(p++));
+ }
+}
+
+void usart_print(char *str)
+{
+ char *p = str;
+ size_t len = 0;
+
+ while (*p++ != '\0') {
+ len++;
+ }
+
+ usart_send((uint8_t *) str, len);
+}
+
+int usart_read_byte(uint8_t *byte)
+{
+ uint16_t timeout = USART_TIMEOUT;
+
+ do {
+ if (UCSR0A & _BV(RXC0)) {
+ *byte = UDR0;
+ return 0;
+ }
+ } while (timeout--);
+
+ return -1;
+}
+
+uint8_t usart_read_byte_nt(void)
+{
+ while ((UCSR0A & _BV(RXC0)) == 0);
+ return UDR0;
+}
+
+
+size_t usart_read(uint8_t *buffer, size_t len)
+{
+ size_t read = 0;
+ uint8_t *p = buffer;
+
+ while (len--) {
+ if (usart_read_byte(p) == 0) {
+ p++;
+ read++;
+ }
+ }
+
+ return read;
+}
+
+int usart_read_line(uint8_t *buffer, size_t len)
+{
+ uint8_t ch;
+ uint8_t *p = buffer;
+ size_t read = 0;
+
+ while (len--) {
+ if (usart_read_byte(&ch) != 0)
+ continue;
+ else
+ read++;
+
+ if (ch == '\n')
+ break;
+ else
+ *(p++) = ch;
+ }
+
+ if (ch != '\n')
+ return -1;
+
+ return 0;
+}