lcd.c

 #include <libopencm3/stm32/f1/rcc.h>                                       
#include <libopencm3/stm32/f1/gpio.h>                                      
#include <libopencm3/stm32/usart.h>                                        
#include "lcd.h"                                                           
#include "mystrlen.h"                                                      
                                                                           
void printlcd(char *message)                                               
{                                                                          
    int len, i;                                                            
    len = mystrlen(message);                                               
    for (i=0; i<len; i++){                                                 
        usart_send_blocking(USART1, message[i]); /* USART1: Send byte. */  
    }                                                                      
}                                                                          
                                                                           
void clearlcd(void)                                                        
{                                                                          
    usart_send_blocking(USART1, LCD_LF); /* Linefeed */                    
    usart_send_blocking(USART1, LCD_LF); /* Linefeed */                    
    usart_send_blocking(USART1, LCD_HOME);                                 
}                                                                          
                                                                           

lcd.h

#ifndef LCD_H
#define LCD_H

#define LCD_LF '\012'
#define LCD_HOME '\001'

void printlcd(char *message);
void clearlcd(void);

#endif
                                
                                
                                
                                
                                
                                
                                

Makefile

##
## This file is part of the libopencm3 project.
##
## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
##
## This library is free software: you can redistribute it and/or modify
## it under the terms of the GNU Lesser General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## This library 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 Lesser General Public License for more details.
##
## You should have received a copy of the GNU Lesser General Public License
## along with this library.  If not, see <http://www.gnu.org/licenses/>.
##

OBJS += mystrlen.o lcd.o
BINARY = usart
LDSCRIPT = $(OPENCM3_DIR)/examples/stm32/f1/stm32vl-discovery/stm32vl-discovery.ld
include $(OPENCM3_DIR)/examples/stm32/f1/Makefile.include

mystrlen.o: mystrlen.h mystrlen.c
    arm-none-eabi-gcc -Wall -pedantic -g -c -o mystrlen.o mystrlen.c -DSTM32F1

lcd.o: lcd.h lcd.c
    arm-none-eabi-gcc -Wall -pedantic -g -c -o lcd.o lcd.c -DSTM32F1

mystrlen.h

#ifndef MYSTRLEN_H
#define MYSTRLEN_H
int mystrlen(char *string);
#endif