From 44c609699d7c08dbcd6f315c44170e96659b24ad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Mon, 18 Jan 2016 16:04:31 +0100
Subject: [PATCH] switch from UART to USART

---
 lib/uart.c | 62 ------------------------------------------------------
 lib/uart.h | 33 -----------------------------
 main.c     | 50 ++++++++++++++++++-------------------------
 3 files changed, 20 insertions(+), 125 deletions(-)
 delete mode 100644 lib/uart.c
 delete mode 100644 lib/uart.h

diff --git a/lib/uart.c b/lib/uart.c
deleted file mode 100644
index 9092abf..0000000
--- a/lib/uart.c
+++ /dev/null
@@ -1,62 +0,0 @@
-/* This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- */
-/* This library handles the USART configuration */
-
-#include <stdint.h> // Standard Integer Types
-#include <stdio.h> // Standard IO facilities
-#include <stdlib.h> // General utilities
-#include <avr/io.h> // AVR device-specific IO definitions
-
-#include "uart.h" // UART header
-#include <util/setbaud.h> // Helper macros for baud rate calculations
-
-/* assign input and output streams */
-FILE uart_output = FDEV_SETUP_STREAM((int (*)(char, struct __file *)) uart_putchar, NULL, _FDEV_SETUP_WRITE);
-FILE uart_input = FDEV_SETUP_STREAM(NULL, (int (*)(struct __file *)) uart_getchar, _FDEV_SETUP_READ);
-FILE uart_io = FDEV_SETUP_STREAM((int (*)(char, struct __file *)) uart_putchar, (int (*)(struct __file *)) uart_getchar, _FDEV_SETUP_RW);
-
-/* configure serial port */
-void uart_init(void)
-{
-	UBRR0H = UBRRH_VALUE; // set baurate (calculated from BAUD)
-	UBRR0L = UBRRL_VALUE; // set baurate (calculated from BAUD)
-#if USE_2X
-	UCSR0A |= (1<<U2X0); // use double speed (set depending on BAUD)
-#else
-	UCSR0A &= ~(1<<U2X0); // do not use double speed (set depending on BAUD)
-#endif
-	UCSR0C = (1<<UCSZ01)|(1<<UCSZ00); // 8N1 bit data
-	UCSR0B = (1<<RXEN0)|(1<<TXEN0);   // enable RX and TX
-	UCSR0B |= (1<<RXCIE0); // enable RX complete interrupt
-}
-
-/* put character on UART stream */
-void uart_putchar(char c, FILE *stream)
-{
-	if (c == '\n') { // add carrier return before line feed. this is recommended for most UART terminals
-		uart_putchar('\r', stream);
-	}
-	while (!(UCSR0A&(1<<UDRE0))); // wait for transmit register to empty
-	UDR0 = c; // put data in transmit register
-	while (!(UCSR0A&(1<<TXC0))); // wait for transmission to complete (else sleep mode can break it)
-	UCSR0A |= (1<<TXC0); // clear transmit flag
-}
-
-/* get character from UART stream (blocking) */
-char uart_getchar(FILE *stream)
-{
-	while (!(UCSR0A&(1<<RXC0))); // wait until data exists
-	return UDR0;
-}
diff --git a/lib/uart.h b/lib/uart.h
deleted file mode 100644
index 569ae0a..0000000
--- a/lib/uart.h
+++ /dev/null
@@ -1,33 +0,0 @@
-/* This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- */
-/* This library handles the USART configuration */
-
-/* set tolerance to 3% to allow 115200 baudrate with 16 MHz clock, else use 9600 for default <2% */
-#define BAUD_TOL 3
-/* serial baudrate, in bits per second (with 8N1 8 bits, no parity bit, 1 stop bit settings) */
-#define BAUD 115200
-
-/* input & output streams */
-FILE uart_output;
-FILE uart_input;
-FILE uart_io;
-
-/* configure serial port */
-void uart_init(void);
-/* put character on UART stream (blocking) */
-void uart_putchar(char c, FILE *stream);
-/* get character from UART stream (blocking) */
-char uart_getchar(FILE *stream);
-
diff --git a/main.c b/main.c
index 0e54b4d..e86bc63 100644
--- a/main.c
+++ b/main.c
@@ -26,7 +26,7 @@
 #include <avr/pgmspace.h> // Program Space Utilities
 #include <avr/sleep.h> // Power Management and Sleep Modes
 
-#include "uart.h" // basic UART functions
+#include "usart.h" // basic USART functions
 #include "main.h" // main definitions
 
 /* help strings */
@@ -46,11 +46,11 @@ PGM_P const help_table[] PROGMEM = {
 };
 
 /* global variables */
-char uart_in[32] = {0}; // user input from USART
-volatile uint8_t uart_in_i = 0; // how many UART characters have been input
+char usart_in[32] = {0}; // user input from USART
+volatile uint8_t usart_in_i = 0; // how many USART characters have been input
 
 /* flags, set in the interrupts and handled in the main program */
-volatile bool uart_flag = false; // UART input data is available
+volatile bool usart_flag = false; // USART input data is available
 
 /* switch off LED */
 void led_off(void)
@@ -162,16 +162,6 @@ void help(void)
 	}
 }
 
-/* save the UART input into a string */
-ISR(USART_RX_vect) { /* UART receive interrupt */
-	uart_in[uart_in_i] = getchar(); // save input
-	if (uart_in_i<sizeof(uart_in)-1) { // go to next if there is space left (else overwrite last)
-		uart_in_i++; // prepare for next character
-		uart_in[uart_in_i] = 0; // always end the string
-	}
-	uart_flag = true; // notify new character is there
-}
-
 /* disable watchdog when booting */
 void wdt_init(void) __attribute__((naked)) __attribute__((section(".init3")));
 void wdt_init(void)
@@ -185,10 +175,10 @@ void wdt_init(void)
 /* initialize GPIO */
 void io_init(void)
 {
-	/* use UART as terminal */
-	uart_init();
-	stdout = &uart_output;
-	stdin  = &uart_input;
+	/* use USART as terminal */
+	usart_init();
+	stdout = &usart_output;
+	stdin  = &usart_input;
 
 	/* gpio */
 	/* LED */
@@ -203,7 +193,7 @@ void command_action()
 {
 	/* split command */
 	const char* delimiter = " ";
-	char* word = strtok(uart_in,delimiter);
+	char* word = strtok(usart_in,delimiter);
 	if (!word) {
 		goto error;
 	}
@@ -280,27 +270,27 @@ error:
 
 int main(void)
 {
-	uint8_t uart_out_i = 0; // how many UART input characters have been processed
+	uint8_t usart_out_i = 0; // how many UART input characters have been processed
 
 	io_init(); // initialize IOs
 	
 	printf(PSTR("welcome to the demo code\n"));
 	while (true) { // endless loop for micro-controller
-		while (uart_flag) { // new UART input
-			uart_flag = false;
-			while (uart_out_i<uart_in_i) {
-				putchar(uart_in[uart_out_i++]); // print current character
+		while (usart_flag) { // new UART input
+			usart_flag = false;
+			while (usart_out_i<usart_in_i) {
+				putchar(usart_in[usart_out_i++]); // print current character
 			}
-			if ('\n'==uart_in[uart_in_i-1] || '\r'==uart_in[uart_in_i-1]) { // end of line detected
-				if ('\r'==uart_in[uart_in_i-1]) { // be sure to print a newline (for windows and mac EOL)
+			if ('\n'==usart_in[usart_in_i-1] || '\r'==usart_in[usart_in_i-1]) { // end of line detected
+				if ('\r'==usart_in[usart_in_i-1]) { // be sure to print a newline (for windows and mac EOL)
 					putchar('\n');
 				}
-				uart_in[uart_in_i-1] = 0; // remove end of line
-				if (uart_in_i>1) { // ignore empty lines
+				usart_in[usart_in_i-1] = 0; // remove end of line
+				if (usart_in_i>1) { // ignore empty lines
 					command_action(); // process command
 				}
-				uart_out_i = 0; // reset output
-				uart_in_i = 0; // reset input
+				usart_out_i = 0; // reset output
+				usart_in_i = 0; // reset input
 			}
 		}
 		/* go to sleep and wait for next interrupt */