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;
+}