trunk/workspace/00_Lib/Serial/UartLibrary/test_uart.c

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+/*************************************************************************
+Title:    example program for the Interrupt controlled UART library
+Author:   Peter Fleury <pfleury@gmx.ch>   http://jump.to/fleury
+File:     $Id: test_uart.c,v 1.5 2012/09/14 17:59:08 peter Exp $
+Software: AVR-GCC 3.4, AVRlibc 1.4
+Hardware: any AVR with built-in UART, tested on AT90S8515 at 4 Mhz
+
+DESCRIPTION:
+          This example shows how to use the UART library uart.c
+
+*************************************************************************/
+#include <stdlib.h>
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <avr/pgmspace.h>
+
+#include "uart.h"
+
+
+/* define CPU frequency in Mhz here if not defined in Makefile */
+#ifndef F_CPU
+#define F_CPU 4000000UL
+#endif
+
+/* 9600 baud */
+#define UART_BAUD_RATE      9600      
+
+
+int main(void)
+{
+    unsigned int c;
+    char buffer[7];
+    int  num=134;
+
+    
+    /*
+     *  Initialize UART library, pass baudrate and AVR cpu clock
+     *  with the macro 
+     *  UART_BAUD_SELECT() (normal speed mode )
+     *  or 
+     *  UART_BAUD_SELECT_DOUBLE_SPEED() ( double speed mode)
+     */
+    uart_init( UART_BAUD_SELECT(UART_BAUD_RATE,F_CPU) ); 
+    
+    /*
+     * now enable interrupt, since UART library is interrupt controlled
+     */
+    sei();
+    
+    /*
+     *  Transmit string to UART
+     *  The string is buffered by the uart library in a circular buffer
+     *  and one character at a time is transmitted to the UART using interrupts.
+     *  uart_puts() blocks if it can not write the whole string to the circular 
+     *  buffer
+     */
+    uart_puts("String stored in SRAM\n");
+    
+    /*
+     * Transmit string from program memory to UART
+     */
+    uart_puts_P("String stored in FLASH\n");
+    
+        
+    /* 
+     * Use standard avr-libc functions to convert numbers into string
+     * before transmitting via UART
+     */     
+    itoa( num, buffer, 10);   // convert interger into string (decimal format)         
+    uart_puts(buffer);        // and transmit string to UART
+
+    
+    /*
+     * Transmit single character to UART
+     */
+    uart_putc('\r');
+    
+    for(;;)
+    {
+        /*
+         * Get received character from ringbuffer
+         * uart_getc() returns in the lower byte the received character and 
+         * in the higher byte (bitmask) the last receive error
+         * UART_NO_DATA is returned when no data is available.
+         *
+         */
+        c = uart_getc();
+        if ( c & UART_NO_DATA )
+        {
+            /* 
+             * no data available from UART 
+             */
+        }
+        else
+        {
+            /*
+             * new data available from UART
+             * check for Frame or Overrun error
+             */
+            if ( c & UART_FRAME_ERROR )
+            {
+                /* Framing Error detected, i.e no stop bit detected */
+                uart_puts_P("UART Frame Error: ");
+            }
+            if ( c & UART_OVERRUN_ERROR )
+            {
+                /* 
+                 * Overrun, a character already present in the UART UDR register was 
+                 * not read by the interrupt handler before the next character arrived,
+                 * one or more received characters have been dropped
+                 */
+                uart_puts_P("UART Overrun Error: ");
+            }
+            if ( c & UART_BUFFER_OVERFLOW )
+            {
+                /* 
+                 * We are not reading the receive buffer fast enough,
+                 * one or more received character have been dropped 
+                 */
+                uart_puts_P("Buffer overflow error: ");
+            }
+            /* 
+             * send received character back
+             */
+            uart_putc( (unsigned char)c );
+        }
+    }
+    
+}