main.cpp

00001 /* mbed Example Program
00002  * Copyright (c) 2006-2014 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 #include "mbed.h"
00017  
00018 // Read temperature from LM75BD
00019 
00020 I2C i2c(I2C_SDA , I2C_SCL ); 
00021 
00022 const int addr7bit = 0x48;      // 7 bit I2C address
00023 const int addr8bit = 0x48 << 1; // 8bit I2C address, 0x90
00024 
00025 int main() {
00026     char cmd[2];
00027     while (1) {
00028         cmd[0] = 0x01;
00029         cmd[1] = 0x00;
00030         i2c.write(addr8bit, cmd, 2);
00031  
00032         wait(0.5);
00033  
00034         cmd[0] = 0x00;
00035         i2c.write(addr8bit, cmd, 1);
00036         i2c.read( addr8bit, cmd, 2);
00037  
00038         float tmp = (float((cmd[0]<<8)|cmd[1]) / 256.0);
00039         printf("Temp = %.2f\n", tmp);
00040     }
00041 }