128 lines
2.9 KiB
Markdown
128 lines
2.9 KiB
Markdown
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# gpio Module
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This module provides access to the GPIO (General Purpose I/O) subsystem.
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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.
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If not using a NodeMCU dev kit, please refer to the below GPIO pin maps for the index<->gpio mapping.
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| IO index | ESP8266 pin | IO index | ESP8266 pin |
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|---------:|:------------|---------:|:------------|
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| 0 [*] | GPIO16 | 7 | GPIO13 |
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| 1 | GPIO5 | 8 | GPIO15 |
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| 2 | GPIO4 | 9 | GPIO3 |
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| 3 | GPIO0 | 10 | GPIO1 |
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| 4 | GPIO2 | 11 | GPIO9 |
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| 5 | GPIO14 | 12 | GPIO10 |
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| 6 | GPIO12 | | |
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** [*] D0(GPIO16) can only be used as gpio read/write. No interrupt support. No pwm/i2c/ow support. **
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## gpio.mode()
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Initialize pin to GPIO mode, set the pin in/out direction, and optional internal pullup.
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####Syntax
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`gpio.mode(pin, mode [, pullup])`
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####Parameters
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- `pin`: pin to configure, IO index
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- `mode`: one of gpio.OUTPUT or gpio.INPUT, or gpio.INT(interrupt mode)
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- `pullup`: gpio.PULLUP or gpio.FLOAT; The default is gpio.FLOAT.
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####Returns
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`nil`
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####Example
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```lua
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gpio.mode(0, gpio.OUTPUT)
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```
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####See also
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- `gpio.read()`
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- `gpio.write()`
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___
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## gpio.read()
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Read digital GPIO pin value.
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####Syntax
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`gpio.read(pin)`
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####Parameters
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- `pin`: pin to read, IO index
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####Returns
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number:0 - low, 1 - high
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####Example
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```lua
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-- read value of gpio 0.
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gpio.read(0)
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```
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####See also
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- `gpio.mode()`
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___
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## gpio.write ()
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Set digital GPIO pin value.
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####Syntax
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`gpio.write(pin, level)`
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####Parameters
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- `pin`: pin to write, IO index
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- `level`: `gpio.HIGH` or `gpio.LOW`
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####Returns
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`nil`
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####Example
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```lua
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-- set pin index 1 to GPIO mode, and set the pin to high.
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pin=1
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gpio.mode(pin, gpio.OUTPUT)
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gpio.write(pin, gpio.HIGH)
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```
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####See also
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- `gpio.mode()`
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- `gpio.read()`
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___
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## gpio.trig()
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Establish a callback function to run on interrupt for a pin.
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There is currently no support for unregistering the callback.
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####Syntax
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`gpio.trig(pin, type [, function(level)])`
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####Parameters
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- `pin`: **1~12**, IO index, pin D0 does not support interrupt.
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- `type`: "up", "down", "both", "low", "high", which represent rising edge, falling edge, both edge, low level, high level trig mode correspondingly.
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- `function(level)`: callback function when triggered. The gpio level is the param. Use previous callback function if undefined here.
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####Returns
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`nil`
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####Example
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```lua
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-- use pin 1 as the input pulse width counter
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pin = 1
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pulse1 = 0
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du = 0
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gpio.mode(pin,gpio.INT)
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function pin1cb(level)
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du = tmr.now() - pulse1
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print(du)
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pulse1 = tmr.now()
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if level == gpio.HIGH then gpio.trig(pin, "down") else gpio.trig(pin, "up") end
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end
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gpio.trig(pin, "down", pin1cb)
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```
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####See also
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- `gpio.mode()`
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___
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