Class: I2CDevice::Driver::GPIO
Overview
Generic software I2C Driver based on /sys/class/gpio. THIS MODULE WORKS WITH VERY SLOW SPEED ABOUT JUST 1kHz (normaly 100kHz).
Constant Summary collapse
- @@DEBUG =
false
Instance Attribute Summary collapse
-
#scl ⇒ Object
readonly
Pin-number of SCL.
-
#sda ⇒ Object
readonly
Pin-number of SDA.
-
#speed ⇒ Object
readonly
Clock speed in kHz.
Class Method Summary collapse
-
.direction(pin, direction) ⇒ Object
:nodoc:.
-
.export(pin) ⇒ Object
:nodoc:.
-
.finalizer(ports) ⇒ Object
:nodoc:.
-
.read(pin) ⇒ Object
:nodoc:.
-
.unexport(pin) ⇒ Object
:nodoc:.
-
.write(pin, val) ⇒ Object
:nodoc:.
Instance Method Summary collapse
-
#i2cget(address, param, length = 1) ⇒ Object
Interface of I2CDevice::Driver.
-
#i2cset(address, *data) ⇒ Object
Interface of I2CDevice::Driver.
-
#initialize(opts = {}) ⇒ GPIO
constructor
opts[:sda]
- Integer
- Pin-number of SDA
opts[:scl]
- Integer
- Pin-number of SCL
[ opts[:speed] = 1 ]
- Integer
-
Clock speed in kHz.
- Pin-number of SCL
- Pin-number of SDA
Constructor Details
#initialize(opts = {}) ⇒ GPIO
opts[:sda]
- Integer
-
Pin-number of SDA
opts[:scl]
- Integer
-
Pin-number of SCL
[ opts[:speed] = 1 ]
- Integer
-
Clock speed in kHz
60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 |
# File 'lib/i2c/driver/gpio.rb', line 60 def initialize(opts={}) @sda = opts[:sda] or raise "opts[:sda] = [gpio pin number] is required" @scl = opts[:scl] or raise "opts[:scl] = [gpio pin number] is required" @speed = opts[:speed] || 1 # kHz but insane @clock = 1.0 / (@speed * 1000) begin GPIO.export(@sda) GPIO.export(@scl) rescue Errno::EBUSY => e end ObjectSpace.define_finalizer(self, self.class.finalizer([@scl, @sda])) begin GPIO.direction(@sda, :high) GPIO.direction(@scl, :high) GPIO.direction(@sda, :in) GPIO.direction(@scl, :in) rescue Errno::EACCES => e # writing to gpio after export is failed in a while retry end end |
Instance Attribute Details
#scl ⇒ Object (readonly)
Pin-number of SCL
53 54 55 |
# File 'lib/i2c/driver/gpio.rb', line 53 def scl @scl end |
#sda ⇒ Object (readonly)
Pin-number of SDA
51 52 53 |
# File 'lib/i2c/driver/gpio.rb', line 51 def sda @sda end |
#speed ⇒ Object (readonly)
Clock speed in kHz
55 56 57 |
# File 'lib/i2c/driver/gpio.rb', line 55 def speed @speed end |
Class Method Details
.direction(pin, direction) ⇒ Object
:nodoc:
23 24 25 26 27 28 |
# File 'lib/i2c/driver/gpio.rb', line 23 def self.direction(pin, direction) #:nodoc: # [:in, :out, :high, :low].include?(direction) or raise "direction must be :in, :out, :high or :low" File.open("/sys/class/gpio/gpio#{pin}/direction", "w") do |f| f.syswrite(direction) end end |
.export(pin) ⇒ Object
:nodoc:
11 12 13 14 15 |
# File 'lib/i2c/driver/gpio.rb', line 11 def self.export(pin) #:nodoc: File.open("/sys/class/gpio/export", "w") do |f| f.syswrite(pin) end end |
.finalizer(ports) ⇒ Object
:nodoc:
42 43 44 45 46 47 48 |
# File 'lib/i2c/driver/gpio.rb', line 42 def self.finalizer(ports) #:nodoc: proc do ports.each do |pin| GPIO.unexport(pin) end end end |
.read(pin) ⇒ Object
:nodoc:
30 31 32 33 34 |
# File 'lib/i2c/driver/gpio.rb', line 30 def self.read(pin) #:nodoc: File.open("/sys/class/gpio/gpio#{pin}/value", "r") do |f| f.sysread(1).to_i end end |
.unexport(pin) ⇒ Object
:nodoc:
17 18 19 20 21 |
# File 'lib/i2c/driver/gpio.rb', line 17 def self.unexport(pin) #:nodoc: File.open("/sys/class/gpio/unexport", "w") do |f| f.syswrite(pin) end end |
.write(pin, val) ⇒ Object
:nodoc:
36 37 38 39 40 |
# File 'lib/i2c/driver/gpio.rb', line 36 def self.write(pin, val) #:nodoc: File.open("/sys/class/gpio/gpio#{pin}/value", "w") do |f| f.syswrite(val ? "1" : "0") end end |
Instance Method Details
#i2cget(address, param, length = 1) ⇒ Object
Interface of I2CDevice::Driver
83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 |
# File 'lib/i2c/driver/gpio.rb', line 83 def i2cget(address, param, length=1) ret = "" start_condition unless write( (address << 1) + 0) raise I2CDevice::I2CIOError, "Unknown slave device (address:#{address})" end write(param) stop_condition # AVR stucked with SCL low without this (Does not AVR support Sr condition?) start_condition unless write( (address << 1) + 1) raise I2CDevice::I2CIOError, "Unknown slave device (address:#{address})" end length.times do |n| ret << read(n != length - 1).chr end ret ensure stop_condition end |
#i2cset(address, *data) ⇒ Object
Interface of I2CDevice::Driver
104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 |
# File 'lib/i2c/driver/gpio.rb', line 104 def i2cset(address, *data) sent = 0 start_condition unless write( (address << 1) + 0) raise I2CDevice::I2CIOError, "Unknown slave device (address:#{address})" end data.each do |c| unless write(c) break end sent += 1 end sent ensure stop_condition end |