98 lines
4.7 KiB
Markdown
98 lines
4.7 KiB
Markdown
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I2C-bus interaction of peripheral sensors with Raspberry PI embedded linux or respective clones
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==============================================================================================
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[](https://travis-ci.org/d2r2/go-i2c)
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[](https://goreportcard.com/report/github.com/d2r2/go-i2c)
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[](https://godoc.org/github.com/d2r2/go-i2c)
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[](./LICENSE)
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This library written in [Go programming language](https://golang.org/) intended to activate and interact with the I2C bus by reading and writing data.
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Compatibility
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-------------
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Tested on Raspberry Pi 1 (model B), Raspberry Pi 3 B+, Banana Pi (model M1), Orange Pi Zero, Orange Pi One.
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Golang usage
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------------
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```go
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func main() {
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// Create new connection to I2C bus on 2 line with address 0x27
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i2c, err := i2c.NewI2C(0x27, 2)
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if err != nil { log.Fatal(err) }
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// Free I2C connection on exit
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defer i2c.Close()
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....
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// Here goes code specific for sending and reading data
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// to and from device connected via I2C bus, like:
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_, err := i2c.Write([]byte{0x1, 0xF3})
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if err != nil { log.Fatal(err) }
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....
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}
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```
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Tutorial
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--------
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My [repositories](https://github.com/d2r2?tab=repositories) contain quite a lot projects, which use i2c library as a starting point to interact with various peripheral devices and sensors for use on embedded Linux devices. All these libraries start with a standard call to open I2C-connection to specific bus line and address, than pass i2c instance to device.
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In its turn, go-i2c use [go-logger](https://github.com/d2r2/go-logger) library to output debug and other notification's lines which produce all necessary levels of logging. You can manage what level of verbosity you would like to see, by adding call:
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```go
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// Uncomment/comment next line to suppress/increase verbosity of output
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logger.ChangePackageLogLevel("i2c", logger.InfoLevel)
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```
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Once you put this call, it will decrease verbosity from default "Debug" up to next "Info" level, reducing the number of low-level console outputs that occur during interaction with the I2C bus. Please, find examples in corresponding I2C-driven sensors among my projects.
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You will find here the list of all devices and sensors supported by me, that reference this library:
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- [Liquid-crystal display driven by Hitachi HD44780 IC](https://github.com/d2r2/go-hd44780).
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- [BMP180/BMP280/BME280 temperature and pressure sensors](https://github.com/d2r2/go-bsbmp).
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- [DHT12/AM2320 humidity and temperature sensors](https://github.com/d2r2/go-aosong).
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- [Si7021 relative humidity and temperature sensor](https://github.com/d2r2/go-si7021).
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- [SHT3x humidity and temperature sensor](https://github.com/d2r2/go-sht3x).
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- [VL53L0X time-of-flight ranging sensor](https://github.com/d2r2/go-vl53l0x).
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- [BH1750 ambient light sensor](https://github.com/d2r2/go-bh1750).
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- [MPL3115A2 pressure and temperature sensor](https://github.com/d2r2/go-mpl3115a2).
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Getting help
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------------
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GoDoc [documentation](http://godoc.org/github.com/d2r2/go-i2c)
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Troubleshooting
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--------------
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- *How to obtain fresh Golang installation to RPi device (either any RPi clone):*
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If your RaspberryPI golang installation taken by default from repository is outdated, you may consider
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to install actual golang manually from official Golang [site](https://golang.org/dl/). Download
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tar.gz file containing armv6l in the name. Follow installation instructions.
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- *How to enable I2C bus on RPi device:*
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If you employ RaspberryPI, use raspi-config utility to activate i2c-bus on the OS level.
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Go to "Interfacing Options" menu, to active I2C bus.
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Probably you will need to reboot to load i2c kernel module.
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Finally you should have device like /dev/i2c-1 present in the system.
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- *How to find I2C bus allocation and device address:*
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Use i2cdetect utility in format "i2cdetect -y X", where X may vary from 0 to 5 or more,
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to discover address occupied by peripheral device. To install utility you should run
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`apt install i2c-tools` on debian-kind system. `i2cdetect -y 1` sample output:
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```
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40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
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50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
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60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
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70: -- -- -- -- -- -- 76 --
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```
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License
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-------
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Go-i2c is licensed under MIT License.
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