Since | Origin / Contributor | Maintainer | Source |
---|---|---|---|
2014-12-22 | Zeroday | Zeroday | gpio.c |
This module provides access to the GPIO (General Purpose Input/Output) subsystem.
All access is based on the I/O index number on the NodeMCU dev kits, not the internal GPIO pin. For example, the D0 pin on the dev kit is mapped to the internal GPIO pin 16.
If not using a NodeMCU dev kit, please refer to the below GPIO pin maps for the index↔gpio mapping.
IO index | ESP8266 pin | IO index | ESP8266 pin |
---|---|---|---|
0 [*] | GPIO16 | 7 | GPIO13 |
1 | GPIO5 | 8 | GPIO15 |
2 | GPIO4 | 9 | GPIO3 |
3 | GPIO0 | 10 | GPIO1 |
4 | GPIO2 | 11 | GPIO9 |
5 | GPIO14 | 12 | GPIO10 |
6 | GPIO12 |
** [*] D0(GPIO16) can only be used as gpio read/write. No support for open-drain/interrupt/pwm/i2c/ow. **
Initialize pin to GPIO mode, set the pin in/out direction, and optional internal weak pull-up.
gpio.mode(pin, mode [, pullup])
pin
pin to configure, IO indexmode
one of gpio.OUTPUT, gpio.OPENDRAIN, gpio.INPUT, or gpio.INT (interrupt mode)pullup
gpio.PULLUP enables the weak pull-up resistor; default is gpio.FLOATnil
gpio.mode(0, gpio.OUTPUT)
Read digital GPIO pin value.
gpio.read(pin)
pin
pin to read, IO index
a number, 0 = low, 1 = high
-- read value of gpio 0.
gpio.read(0)
Serialize output based on a sequence of delay-times. After each delay, the pin is toggled.
gpio.serout(pin, start_level, delay_times [, repeat_num])
pin
pin to use, IO indexstart_level
level to start on, either gpio.HIGH
or gpio.LOW
delay_times
an array of delay times between each toggle of the gpio pin.repeat_num
an optional number of times to run through the sequence.Note that this function blocks, and as such any use of it must adhere to the SDK guidelines of time spent blocking the stack (10-100ms). Failure to do so may lead to WiFi issues or outright crashes/reboots.
nil
gpio.mode(1,gpio.OUTPUT,gpio.PULLUP)
gpio.serout(1,1,{30,30,60,60,30,30}) -- serial one byte, b10110010
gpio.serout(1,1,{30,70},8) -- serial 30% pwm 10k, lasts 8 cycles
gpio.serout(1,1,{3,7},8) -- serial 30% pwm 100k, lasts 8 cycles
gpio.serout(1,1,{0,0},8) -- serial 50% pwm as fast as possible, lasts 8 cycles
gpio.serout(1,0,{20,10,10,20,10,10,10,100}) -- sim uart one byte 0x5A at about 100kbps
gpio.serout(1,1,{8,18},8) -- serial 30% pwm 38k, lasts 8 cycles
Establish or clear a callback function to run on interrupt for a pin.
This function is not available if GPIO_INTERRUPT_ENABLE was undefined at compile time.
gpio.trig(pin, [type [, callback_function]])
pin
1-12, pin to trigger on, IO index. Note that pin 0 does not support interrupts.type
«up», «down», «both», «low», «high», which represent rising edge, falling edge, both
edges, low level, and high level trigger modes respectivey. If the type is «none» or omitted
then the callback function is removed and the interrupt is disabled.callback_function(level)
callback function when trigger occurs. The level of the specified pin
at the interrupt passed as the parameter to the callback. The previous callback function will be
used if the function is omitted.nil
do
-- use pin 1 as the input pulse width counter
local pin, pulse1, du, now, trig = 1, 0, 0, tmr.now, gpio.trig
gpio.mode(pin,gpio.INT)
local function pin1cb(level)
local pulse2 = now()
print( level, pulse2 - pulse1 )
pulse1 = pulse2
trig(pin, level == gpio.HIGH and "down" or "up")
end
trig(pin, "down", pin1cb)
end
Set digital GPIO pin value.
gpio.write(pin, level)
pin
pin to write, IO indexlevel
gpio.HIGH
or gpio.LOW
nil
-- set pin index 1 to GPIO mode, and set the pin to high.
pin=1
gpio.mode(pin, gpio.OUTPUT)
gpio.write(pin, gpio.HIGH)