162 lines
4.5 KiB
Markdown
162 lines
4.5 KiB
Markdown
# GPIO Module
|
|
| Since | Origin / Contributor | Maintainer | Source |
|
|
| :----- | :-------------------- | :---------- | :------ |
|
|
| 2014-12-22 | [Zeroday](https://github.com/funshine) | [Zeroday](https://github.com/funshine) | [gpio.c](../../../app/modules/gpio.c)|
|
|
|
|
|
|
This module provides access to the [GPIO](https://en.wikipedia.org/wiki/General-purpose_input/output) (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 interrupt support. No pwm/i2c/ow support. **
|
|
|
|
|
|
## gpio.mode()
|
|
|
|
Initialize pin to GPIO mode, set the pin in/out direction, and optional internal pullup.
|
|
|
|
#### Syntax
|
|
`gpio.mode(pin, mode [, pullup])`
|
|
|
|
#### Parameters
|
|
- `pin` pin to configure, IO index
|
|
- `mode` one of gpio.OUTPUT or gpio.INPUT, or gpio.INT(interrupt mode)
|
|
- `pullup` gpio.PULLUP or gpio.FLOAT; default is gpio.FLOAT
|
|
|
|
#### Returns
|
|
`nil`
|
|
|
|
#### Example
|
|
```lua
|
|
gpio.mode(0, gpio.OUTPUT)
|
|
```
|
|
#### See also
|
|
- [`gpio.read()`](#gpioread)
|
|
- [`gpio.write()`](#gpiowrite)
|
|
|
|
## gpio.read()
|
|
|
|
Read digital GPIO pin value.
|
|
|
|
#### Syntax
|
|
`gpio.read(pin)`
|
|
|
|
#### Parameters
|
|
`pin` pin to read, IO index
|
|
|
|
#### Returns
|
|
a number, 0 = low, 1 = high
|
|
|
|
#### Example
|
|
```lua
|
|
-- read value of gpio 0.
|
|
gpio.read(0)
|
|
```
|
|
#### See also
|
|
[`gpio.mode()`](#gpiomode)
|
|
|
|
## gpio.serout()
|
|
|
|
Serialize output based on a sequence of delay-times. After each delay, the pin is toggled.
|
|
|
|
#### Syntax
|
|
`gpio.serout(pin, start_level, delay_times [, repeat_num])`
|
|
|
|
#### Parameters
|
|
- `pin` pin to use, IO index
|
|
- `start_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.
|
|
|
|
#### Returns
|
|
`nil`
|
|
|
|
#### Example
|
|
```lua
|
|
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
|
|
```
|
|
|
|
## gpio.trig()
|
|
|
|
Establish a callback function to run on interrupt for a pin.
|
|
|
|
There is currently no support for unregistering the callback.
|
|
|
|
This function is not available if GPIO_INTERRUPT_ENABLE was undefined at compile time.
|
|
|
|
#### Syntax
|
|
`gpio.trig(pin, type [, function(level)])`
|
|
|
|
#### Parameters
|
|
- `pin` **1~12**, IO index, pin D0 does not support interrupt.
|
|
- `type` "up", "down", "both", "low", "high", which represent rising edge, falling edge, both edge, low level, high level trig mode correspondingly.
|
|
- `function(level)` callback function when triggered. The gpio level is the param. Use previous callback function if undefined here.
|
|
|
|
#### Returns
|
|
`nil`
|
|
|
|
#### Example
|
|
|
|
```lua
|
|
-- use pin 1 as the input pulse width counter
|
|
pin = 1
|
|
pulse1 = 0
|
|
du = 0
|
|
gpio.mode(pin,gpio.INT)
|
|
function pin1cb(level)
|
|
du = tmr.now() - pulse1
|
|
print(du)
|
|
pulse1 = tmr.now()
|
|
if level == gpio.HIGH then gpio.trig(pin, "down") else gpio.trig(pin, "up") end
|
|
end
|
|
gpio.trig(pin, "down", pin1cb)
|
|
|
|
```
|
|
#### See also
|
|
[`gpio.mode()`](#gpiomode)
|
|
|
|
## gpio.write()
|
|
|
|
Set digital GPIO pin value.
|
|
|
|
#### Syntax
|
|
`gpio.write(pin, level)`
|
|
|
|
#### Parameters
|
|
- `pin` pin to write, IO index
|
|
- `level` `gpio.HIGH` or `gpio.LOW`
|
|
|
|
#### Returns
|
|
`nil`
|
|
|
|
#### Example
|
|
```lua
|
|
-- 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)
|
|
```
|
|
#### See also
|
|
- [`gpio.mode()`](#gpiomode)
|
|
- [`gpio.read()`](#gpioread)
|