106 lines
2.9 KiB
C
106 lines
2.9 KiB
C
/*
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=================================================================================
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Name : rtc_ds1307.c
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Version : 0.1
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Copyright (C) 2012 by Andre Wussow, 2012, desk@binerry.de
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Description :
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A simple test for querying the RTC DS1307.
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Connection (http://www.raspberrypi.org/archives/384):
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DS1307 pins Raspberry Pi Other
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1 - X1 Clock oscillator X1
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2 - X2 Clock oscillator X2
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3 - VBat Coin cell battery CR2032 3V
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4 - GND P05 - GND
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5 - Vcc P01 - 5V
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6 - SQW/OUT
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7 - SCL P04 - SCL0
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8 - SDA P02 - SDA0
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References :
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http://binerry.de/post/26685647322/raspberry-pi-and-i2c
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http://pdfserv.maxim-ic.com/en/ds/DS1307.pdf
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================================================================================
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This sample is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This sample is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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================================================================================
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*/
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#include <stdio.h>
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#include <fcntl.h>
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#include <linux/i2c-dev.h>
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#include <linux/i2c.h>
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int main (void)
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{
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// print infos
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printf("Raspberry Pi RTC DS1307 Sample\n");
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printf("========================================\n");
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int deviceHandle;
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int readBytes;
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char buffer[7];
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// initialize buffer
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buffer[0] = 0x00;
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// address of DS1307 RTC device
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int deviceI2CAddress = 0x68;
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// open device on /dev/i2c-0
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if ((deviceHandle = open("/dev/i2c-0", O_RDWR)) < 0) {
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printf("Error: Couldn't open device! %d\n", deviceHandle);
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return 1;
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}
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// connect to DS1307 as i2c slave
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if (ioctl(deviceHandle, I2C_SLAVE, deviceI2CAddress) < 0) {
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printf("Error: Couldn't find device on address!\n");
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return 1;
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}
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// begin transmission and request acknowledgement
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readBytes = write(deviceHandle, buffer, 1);
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if (readBytes != 1)
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{
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printf("Error: Received no ACK-Bit, couldn't established connection!");
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}
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else
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{
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// read response
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readBytes = read(deviceHandle, buffer, 7);
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if (readBytes != 7)
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{
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printf("Error: Received no data!");
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}
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else
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{
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// get data
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int seconds = buffer[0]; // 0-59
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int minutes = buffer[1]; // 0-59
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int hours = buffer[2]; // 1-23
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int dayOfWeek = buffer[3]; // 1-7
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int day = buffer[4]; // 1-28/29/30/31
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int month = buffer[5]; // 1-12
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int year = buffer[6]; // 0-99;
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// and print results
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printf("Actual RTC-time:\n");
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printf("Date: %x-%x-%x\n", year, month, day);
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printf("Time: %x:%x:%x\n", hours, minutes, seconds);
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}
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}
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// close connection and return
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close(deviceHandle);
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return 0;
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} |