mirror of
https://github.com/clockworkpi/WiringPi.git
synced 2025-12-13 00:08:51 +01:00
25e4ec570b
delayMicrosecondsHard re-written - again. Added a serialRead example program, and added in the okLed to the examples too. Updated/checked some of the GPIO/PWM code. Added in some experimental servo and tone generating code and and example or 2. Tweaks to the gpio command to correctly load the I2C modules too.
118 lines
3.3 KiB
C
118 lines
3.3 KiB
C
/*
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* wiringPiSPI.c:
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* Simplified SPI access routines
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* Copyright (c) 2012 Gordon Henderson
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***********************************************************************
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* This file is part of wiringPi:
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* https://projects.drogon.net/raspberry-pi/wiringpi/
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*
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* wiringPi is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* wiringPi 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
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with wiringPi.
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* If not, see <http://www.gnu.org/licenses/>.
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***********************************************************************
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*/
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#include <stdint.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <linux/spi/spidev.h>
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#include "wiringPiSPI.h"
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// The SPI bus parameters
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// Variables as they need to be passed as pointers later on
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static char *spiDev0 = "/dev/spidev0.0" ;
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static char *spiDev1 = "/dev/spidev0.1" ;
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static uint8_t spiMode = 0 ;
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static uint8_t spiBPW = 8 ;
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static uint16_t spiDelay = 0;
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static uint32_t spiSpeeds [2] ;
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static int spiFds [2] ;
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/*
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* wiringPiSPIGetFd:
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* Return the file-descriptor for the given channel
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*********************************************************************************
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*/
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int wiringPiSPIGetFd (int channel)
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{
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return spiFds [channel & 1] ;
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}
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/*
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* wiringPiSPIDataRW:
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* Write and Read a block of data over the SPI bus.
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* Note the data ia being read into the transmit buffer, so will
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* overwrite it!
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* This is also a full-duplex operation.
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*********************************************************************************
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*/
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int wiringPiSPIDataRW (int channel, unsigned char *data, int len)
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{
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struct spi_ioc_transfer spi ;
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channel &= 1 ;
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spi.tx_buf = (unsigned long)data ;
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spi.rx_buf = (unsigned long)data ;
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spi.len = len ;
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spi.delay_usecs = spiDelay ;
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spi.speed_hz = spiSpeeds [channel] ;
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spi.bits_per_word = spiBPW ;
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return ioctl (spiFds [channel], SPI_IOC_MESSAGE(1), &spi) ;
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}
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/*
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* wiringPiSPISetup:
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* Open the SPI device, and set it up, etc.
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*********************************************************************************
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*/
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int wiringPiSPISetup (int channel, int speed)
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{
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int fd ;
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channel &= 1 ;
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if ((fd = open (channel == 0 ? spiDev0 : spiDev1, O_RDWR)) < 0)
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return -1 ;
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spiSpeeds [channel] = speed ;
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spiFds [channel] = fd ;
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// Set SPI parameters.
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// Why are we reading it afterwriting it? I've no idea, but for now I'm blindly
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// copying example code I've seen online...
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if (ioctl (fd, SPI_IOC_WR_MODE, &spiMode) < 0) return -1 ;
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if (ioctl (fd, SPI_IOC_RD_MODE, &spiMode) < 0) return -1 ;
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if (ioctl (fd, SPI_IOC_WR_BITS_PER_WORD, &spiBPW) < 0) return -1 ;
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if (ioctl (fd, SPI_IOC_RD_BITS_PER_WORD, &spiBPW) < 0) return -1 ;
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if (ioctl (fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) < 0) return -1 ;
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if (ioctl (fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) < 0) return -1 ;
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return fd ;
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}
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