esp8266_easygpio

An easy way of setting up esp8266 GPIO pins.

I grew tired of juggling gpio pin numbers, gpio names and gpio functions. So i created this little helper library.

To setup a pin as a GPIO input you can now just do this:

#include "easygpio/easygpio.h"
...
bool easygpio_pinMode(0, EASYGPIO_NOPULL, EASYGPIO_INPUT);

Same thing with outputs:

bool easygpio_pinMode(1, EASYGPIO_NOPULL, EASYGPIO_OUTPUT);

pullStatus does not apply to output pins.

You might still need the gpio_name and func. No problem:

bool easygpio_getGPIONameFunc(uint8_t gpio_pin, uint32_t *gpio_name, uint8_t *gpio_func)

You can even setup an interrupt handler:

bool easygpio_attachInterrupt(uint8_t gpio_pin, EasyGPIO_PullStatus pullStatus, void (*interruptHandler)(void* arg), void *interruptArg)

You can use the methods and macros defined in gpio.h (from the sdk) to access the 'standard' gpio pins (not GPIO16).

#include "gpio.h"
...
GPIO_OUTPUT_SET(gpio_no, bit_value) // GPIO_OUTPUT_SET(0,1) sets gpio0 to high
GPIO_DIS_OUTPUT(gpio_no) // GPIO_DIS_OUTPUT(2) turns off output on gpio2
GPIO_INPUT_GET(gpio_no) // GPIO_INPUT_GET(12) returns the input value of gpio12

To access all of the pins in an uniform way you can use

uint8_t easygpio_inputGet(uint8_t gpio_pin);
void easygpio_outputSet(uint8_t gpio_pin, uint8_t value);

However, you should not rely on that these methods will change input/output status of a pin (like the gpio.h macros does).

e.g. if you call easygpio_outputSet on an input pin, the pin may or may not remain an input. This is because of performance and uniformity reasons. easygpio_outputSet(16,1) will never flip gpio16 to an output, and we can't have access methods with different semantics depending on pin number).

So if you need to change the input/output mode of a pin on the fly, you can use easygpio_outputDisable() or easygpio_outputEnable().

###Available pins

Pin number	Note
GPIO0	this pin selects bootmode (pull up for normal boot)
GPIO1	normally UART0 TX
GPIO2	this pin selects bootmode (pull up for normal boot)
GPIO3	normally UART0 RX (you can use stdout to use it as GPIO)
GPIO4	sometimes mislabeled as GPIO5 (esp-12)
GPIO5	sometimes mislabeled as GPIO4 (esp-12)
GPIO12
GPIO13
GPIO14
GPIO15	this pin selects bootmode (pull down for normal boot)
GPIO16	requires easygpio_inputGet() & easygpio_outputSet() access methods (no interrupt on this pin)

All the GPIOs mentioned in easgle_soc.h are supported, but maybe we should not mess with the internal SPI pins for GPIO.

Usage

The project has been designed for easy reuse, just create a folder with these files in it (git subtree works great for that purpose). Then point your MODULES variable (or whatever subdirectory construct you use) in the Makefile to that folder . If you find yourself manually copying these individial .c and .h files - you're doing it wrong.

See an example on how this library can be used here, here, here, here - bha.. practically all of my esp projects uses it.

Todo

• Find the correct READ_PERI_REG() address for easygpio_inputGet(), now it's simply using GPIO_INPUT_GET()

Required:

esp-open-sdk-v0.9.5 or higher.

I've successfully tested this with sdk v1.5.2 and v0.9.5 (linux & mac).