Module: Beaglebone::GPIO
- Defined in:
- lib/beaglebone/gpio.rb
Overview
GPIO
procedural methods for GPIO control
Summary
#pin_mode is called to initialize a pin. Further basic functionality is available with #digital_read and #digital_write
Constant Summary collapse
- MODES =
GPIO modes
[ :IN, :OUT ]
- STATES =
GPIO states
{ :HIGH => 1, :LOW => 0 }
- EDGES =
Edge trigger options
[ :NONE, :RISING, :FALLING, :BOTH ]
- SLEWRATES =
Slew rates
[ :SLOW, :FAST ]
- PULLMODES =
pull modes
[ :PULLUP, :PULLDOWN, :NONE ]
- GPIOTEMPLATE =
dts template for GPIO pin
'/* * This is a template-generated file */ /dts-v1/; /plugin/; /{ compatible = "ti,beaglebone", "ti,beaglebone-black"; part_number = "BS_PINMODE_!PIN_KEY!_!DATA!"; exclusive-use = "!PIN_DOT_KEY!", "!PIN_FUNCTION!"; fragment@0 { target = <&am33xx_pinmux>; __overlay__ { bs_pinmode_!PIN_KEY!_!DATA!: pinmux_bs_pinmode_!PIN_KEY!_!DATA! { pinctrl-single,pins = <!PIN_OFFSET! !DATA!>; }; }; }; fragment@1 { target = <&ocp>; __overlay__ { bs_pinmode_!PIN_KEY!_!DATA!_pinmux { compatible = "bone-pinmux-helper"; status = "okay"; pinctrl-names = "default"; pinctrl-0 = <&bs_pinmode_!PIN_KEY!_!DATA!>; }; }; }; }; '
Class Method Summary collapse
-
.cleanup ⇒ Object
Resets all the GPIO pins that we have used and unexport them.
-
.digital_read(pin) ⇒ Symbol
Reads a pin’s input state and return that value.
-
.digital_write(pin, state) ⇒ Object
Sets a pin’s output state.
-
.disable_gpio_pin(pin) ⇒ Object
Disable a GPIO pin.
-
.enabled?(pin) ⇒ Boolean
Returns true if specified pin is enabled in GPIO mode, else false.
-
.get_gpio_edge(pin) ⇒ Symbol
Returns the GPIO edge trigger type on an initialized pin.
-
.get_gpio_mode(pin) ⇒ Object
Returns mode from
pin
, reads mode if unknown. -
.get_gpio_pins ⇒ Array<Symbol>
Return an array of GPIO pins in use.
-
.get_gpio_state(pin) ⇒ Object
Returns last known state from
pin
, reads state if unknown. -
.pin_mode(pin, mode, pullmode = nil, slewrate = nil) ⇒ Object
Initialize a GPIO pin.
-
.run_on_edge(callback, pin, edge, timeout = nil, repeats = nil) ⇒ Object
Runs a callback on an edge trigger event.
-
.run_once_on_edge(callback, pin, edge, timeout = nil) ⇒ Object
Runs a callback one time on an edge trigger event.
-
.set_gpio_edge(pin, edge, force = nil) ⇒ Object
Set GPIO edge trigger type on an initialized pin.
-
.set_gpio_mode(pin, mode) ⇒ Object
Set GPIO mode on an initialized pin.
-
.shift_out(latch_pin, clock_pin, data_pin, data, lsb = nil) ⇒ Object
Sends data to a shift register.
-
.stop_edge_wait(pin) ⇒ Object
Stops any threads waiting for data on specified pin.
-
.wait_for_edge(pin, edge, timeout = nil, disable = true) ⇒ Object
Wait for an edge trigger.
Class Method Details
.cleanup ⇒ Object
Resets all the GPIO pins that we have used and unexport them
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# File 'lib/beaglebone/gpio.rb', line 277 def cleanup get_gpio_pins.each { |x| disable_gpio_pin(x) } end |
.digital_read(pin) ⇒ Symbol
Reads a pin’s input state and return that value
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# File 'lib/beaglebone/gpio.rb', line 166 def digital_read(pin) check_gpio_enabled(pin) raise StandardError, "PIN not in GPIO IN mode: #{pin}" unless get_gpio_mode(pin) == :IN fd = get_value_fd(pin) fd.rewind value = fd.read.to_s.strip state = STATES.key(value.to_i) Beaglebone::set_pin_status(pin, :state, state) end |
.digital_write(pin, state) ⇒ Object
Sets a pin’s output state
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# File 'lib/beaglebone/gpio.rb', line 146 def digital_write(pin, state) check_valid_state(state) check_gpio_enabled(pin) raise StandardError, "PIN not in GPIO OUT mode: #{pin}" unless get_gpio_mode(pin) == :OUT fd = get_value_fd(pin) fd.write STATES[state.to_sym].to_s fd.flush Beaglebone::set_pin_status(pin, :state, state) end |
.disable_gpio_pin(pin) ⇒ Object
Disable a GPIO pin
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# File 'lib/beaglebone/gpio.rb', line 420 def disable_gpio_pin(pin) Beaglebone::check_valid_pin(pin, :gpio) pininfo = PINS[pin] close_value_fd(pin) #close any running threads stop_edge_wait(pin) #write to unexport to disable gpio begin File.open('/sys/class/gpio/unexport', 'w') { |f| f.write(pininfo[:gpio]) } rescue # end #unload device tree Beaglebone::device_tree_unload("#{TREES[:GPIO][:pin]}#{pin}_.*") unless pininfo[:led] #remove status from hash so following enabled? call checks actual system Beaglebone::delete_pin_status(pin) #check to see if pin is GPIO enabled in /sys/class/gpio/ raise StandardError, "GPIO was unable to uninitalize pin: #{pin.to_s}" if enabled?(pin) end |
.enabled?(pin) ⇒ Boolean
Returns true if specified pin is enabled in GPIO mode, else false
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# File 'lib/beaglebone/gpio.rb', line 282 def enabled?(pin) return true if Beaglebone::get_pin_status(pin, :type) == :gpio return false unless valid?(pin) if Dir.exists?(gpio_directory(pin)) Beaglebone::set_pin_status(pin, :type, :gpio) return true end false end |
.get_gpio_edge(pin) ⇒ Symbol
Returns the GPIO edge trigger type on an initialized pin
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# File 'lib/beaglebone/gpio.rb', line 398 def get_gpio_edge(pin) check_gpio_enabled(pin) edge = Beaglebone::get_pin_status(pin, :trigger) return edge if edge read_gpio_edge(pin) end |
.get_gpio_mode(pin) ⇒ Object
Returns mode from pin
, reads mode if unknown
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# File 'lib/beaglebone/gpio.rb', line 339 def get_gpio_mode(pin) check_gpio_enabled(pin) mode = Beaglebone::get_pin_status(pin, :mode) return mode if mode read_gpio_direction(pin) end |
.get_gpio_pins ⇒ Array<Symbol>
Return an array of GPIO pins in use
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# File 'lib/beaglebone/gpio.rb', line 413 def get_gpio_pins Beaglebone.pinstatus.clone.select { |x,y| x if y[:type] == :gpio && !PINS[x][:led] }.keys end |
.get_gpio_state(pin) ⇒ Object
Returns last known state from pin
, reads state if unknown
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# File 'lib/beaglebone/gpio.rb', line 328 def get_gpio_state(pin) check_gpio_enabled(pin) state = Beaglebone::get_pin_status(pin, :state) return state if state digital_read(pin) end |
.pin_mode(pin, mode, pullmode = nil, slewrate = nil) ⇒ Object
Initialize a GPIO pin
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# File 'lib/beaglebone/gpio.rb', line 70 def pin_mode(pin, mode, pullmode = nil, slewrate = nil) #make sure a valid mode was passed check_valid_mode(mode) #make sure a valid pin was passed and that it supports GPIO Beaglebone::check_valid_pin(pin, :gpio) #get info from PINS hash pininfo = PINS[pin] #if pin is enabled for something else, disable it if Beaglebone::get_pin_status(pin) && Beaglebone::get_pin_status(pin, :type) != :gpio Beaglebone::disable_pin(pin) end pullmode = pullmode || :PULLUP slewrate = slewrate || :FAST raise ArgumentError, "Invalid Slew Rate (#{slewrate}) specified on: #{pin}" unless SLEWRATES.include?(slewrate) raise ArgumentError, "Invalid Pull Mode (#{pullmode}) specified on: #{pin}" unless PULLMODES.include?(pullmode) if mode == :IN and pullmode != :PULLUP and ( pininfo[:mmc] or pin == :P9_15 ) raise ArgumentError, "Invalid Pull mode specified for pin: #{pin} (#{pullmode})" end #export pin unless its an on board LED, if it isn't already exported if pininfo[:led] raise StandardError, "LEDs only support OUT mode: #{pin.to_s}" unless mode == :OUT File.open("#{gpio_directory(pin)}/trigger", 'w') { |f| f.write('gpio') } else # if pin is not an onboard LED # create device tree overlay for this pin, do not force rebuild pin_data = create_device_tree(pin, mode, pullmode, slewrate, false) # unload previous dtb if loaded begin Beaglebone::device_tree_unload("#{TREES[:GPIO][:pin]}#{pin}_.*") rescue # end # load device tree overlay Beaglebone::device_tree_load("#{TREES[:GPIO][:pin]}#{pin}_0x#{pin_data.to_s(16)}") # export gpio pin begin File.open('/sys/class/gpio/export', 'w') { |f| f.write pininfo[:gpio] } rescue # end #check to see if pin is GPIO enabled in /sys/class/gpio/ raise StandardError, "GPIO was unable to initalize pin: #{pin.to_s}" unless enabled?(pin) end unless Beaglebone::get_pin_status(pin, :type) == :gpio #set pin mode unless pininfo[:led] set_gpio_mode(pin, mode) dir = read_gpio_direction(pin) raise StandardError, "GPIO was unable to set mode: #{pin.to_s} to #{mode.to_s} (#{dir})" if mode != dir end Beaglebone::set_pin_status(pin, :mode, mode) end |
.run_on_edge(callback, pin, edge, timeout = nil, repeats = nil) ⇒ Object
Runs a callback on an edge trigger event. This creates a new thread that runs in the background
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# File 'lib/beaglebone/gpio.rb', line 190 def run_on_edge(callback, pin, edge, timeout = nil, repeats=nil) raise StandardError, "Already waiting for trigger on pin: #{pin}" if Beaglebone::get_pin_status(pin, :trigger) raise StandardError, "Already waiting for trigger on pin: #{pin}" if Beaglebone::get_pin_status(pin, :thread) thread = Thread.new(callback, pin, edge, timeout, repeats) do |c, p, e, t, r| begin count = 0 loop do state = wait_for_edge(p, e, t, false) c.call(p, state, count) if c count += 1 break if r && count >= r end rescue => ex puts ex puts ex.backtrace ensure cleanup_edge_trigger(p) end end Beaglebone::set_pin_status(pin, :thread, thread) end |
.run_once_on_edge(callback, pin, edge, timeout = nil) ⇒ Object
Runs a callback one time on an edge trigger event. This is a convenience method for run_on_edge
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# File 'lib/beaglebone/gpio.rb', line 220 def run_once_on_edge(callback, pin, edge, timeout = nil) run_on_edge(callback, pin, edge, timeout, 1) end |
.set_gpio_edge(pin, edge, force = nil) ⇒ Object
Set GPIO edge trigger type on an initialized pin
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# File 'lib/beaglebone/gpio.rb', line 373 def set_gpio_edge(pin, edge, force=nil) check_valid_edge(edge) Beaglebone::check_valid_pin(pin, :gpio) raise StandardError, "PIN not in GPIO IN mode: #{pin}" unless get_gpio_mode(pin) == :IN return if get_gpio_edge(pin) == edge && !force File.open("#{gpio_directory(pin)}/edge", 'w') { |f| f.write edge.to_s.downcase } testedge = read_gpio_edge(pin) if testedge != edge.to_s.downcase Beaglebone::delete_pin_status(pin, :trigger) raise StandardError, "GPIO was unable to set edge: #{pin.to_s} to #{edge.to_s}" end if edge.to_sym == :NONE Beaglebone::delete_pin_status(pin, :trigger) else Beaglebone::set_pin_status(pin, :trigger, edge.to_sym) end end |
.set_gpio_mode(pin, mode) ⇒ Object
Set GPIO mode on an initialized pin
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# File 'lib/beaglebone/gpio.rb', line 356 def set_gpio_mode(pin, mode) Beaglebone::check_valid_pin(pin, :gpio) check_valid_mode(mode) check_gpio_enabled(pin) File.open("#{gpio_directory(pin)}/direction", 'w') { |f| f.write mode.to_s.downcase } Beaglebone::set_pin_status(pin, :mode, mode) end |
.shift_out(latch_pin, clock_pin, data_pin, data, lsb = nil) ⇒ Object
Sends data to a shift register
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# File 'lib/beaglebone/gpio.rb', line 306 def shift_out(latch_pin, clock_pin, data_pin, data, lsb=nil) raise ArgumentError, "data must be > 0 (#{data})" if data < 0 digital_write(latch_pin, :LOW) binary = data.to_s(2) pad = 8 - ( binary.size % 8 ) binary = ( '0' * pad ) + binary if pad.between?(1,7) binary.reverse! if lsb binary.each_char do |bit| digital_write(clock_pin, :LOW) digital_write(data_pin, bit == '0' ? :LOW : :HIGH) digital_write(clock_pin, :HIGH) end digital_write(latch_pin, :HIGH) data end |
.stop_edge_wait(pin) ⇒ Object
Stops any threads waiting for data on specified pin
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# File 'lib/beaglebone/gpio.rb', line 227 def stop_edge_wait(pin) thread = Beaglebone::get_pin_status(pin, :thread) thread.exit if thread thread.join if thread end |
.wait_for_edge(pin, edge, timeout = nil, disable = true) ⇒ Object
Wait for an edge trigger. Returns the type that triggered the event, e.g. :RISING, :FALLING, :BOTH
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# File 'lib/beaglebone/gpio.rb', line 246 def wait_for_edge(pin, edge, timeout = nil, disable=true) check_valid_edge(edge) raise ArgumentError, "Cannot wait for edge trigger NONE: #{pin}" if edge.to_sym == :NONE check_gpio_enabled(pin) raise StandardError, "PIN not in GPIO IN mode: #{pin}" unless get_gpio_mode(pin) == :IN #ensure we're the only ones waiting for this trigger if Beaglebone::get_pin_status(pin, :thread) && Beaglebone::get_pin_status(pin, :thread) != Thread.current raise StandardError, "Already waiting for trigger on pin: #{pin}" end if Beaglebone::get_pin_status(pin, :trigger) && Beaglebone::get_pin_status(pin, :thread) != Thread.current raise StandardError, "Already waiting for trigger on pin: #{pin}" end set_gpio_edge(pin, edge) fd = get_value_fd(pin) fd.read #select will return fd into the error set "es" if it recieves an interrupt _, _, es = IO.select(nil, nil, [fd], timeout) set_gpio_edge(pin, :NONE) if disable es ? digital_read(pin) : nil end |