GPIOs Configuration

THIS IS STILL IN A BETA STAGE AND CAN CHANGE

Since HAA V12 Merlin, GPIOs behavior must be configured in an array to determine how hardware will work.

This array is declared by the key "io":[...] and contains other arrays. Each other array is a group of GPIOs declaration.

By default, GPIOs are disabled, but they must be configured as INPUT, OUTPUT, OPEN-DRAIN... with different options, like pull-up resistors, modes, PWM...

Structure of "io":[...] array is:

"io" : [ 
  [ [ gpio 1, gpio 2, gpio N, ...], mode, pull-up/down, options... ], 
  [ [ gpio 1, gpio 2, gpio N, ...], mode, pull-up/down, options... ], 
  [ [ gpio 1, gpio 2, gpio N, ...], mode, pull-up/down, options... ], 
  ...
]

• [ gpio 1, gpio 2, gpio N, ...] is a GPIO array, according to hardware. All GPIO numbers into this array will have same configuration as follow.
• mode is the main operation mode for these [ gpios ].

Depending of selected mode, different options are available.

ADC pin of ESP8266 doesn't need any declaration here.

- Options with * are available only for ESP32 models. They are incompatible with ESP8266 models.

Mode	Description
0	Disable (default)
1	Input only
2	Output only
3	Output only with open-drain
4	* Output and input with open-drain
5	* Output and input
6	Input only with binary input (button/switch) support
7	PWM Software only output
8	PWM Software only output with open-drain
10	* ADC Input

Depending on the hardware attached to a GPIO there may be a need for enabling an internal pull-up or pull-down resistor.

Pull-up/down	Description
-1	Don't apply any pull-up/down setting to GPIO and leave it as SDK init.
0	Floating. Disable internal pull-up and pull-down resistors. (default)
1	Enable internal pull-up resistor
2	* Enable internal pull-down resistor
3	* Enable internal pull-up and pull-down resistors

Modes 2, 3, 4 and 5. Output options:

[ [ gpios ], mode, pull-up/down, initial value ]

Initial value	Description
0	Set GPIO output to LOW value (default)
1	Set GPIO output to HIGH value

Mode 6. Input only with binary input (button/switch) support options:

If MCP23017 interfaces are used, remember to use hundreds to select MCP23017 of GPIO. For example, GPIO 6 of first MCP23017 will be 106.

[ [ gpios ], mode, pull-up/down, button mode, button filter ]

With some peripherals and hardware the actual GPIO signal may need to be inverted to ensure the correct action is performed when the GPIO changes state. This is normal for binary inputs that are active low.

Button mode	Description
0	Normal input (default)
1	Inverted input
2	Normal input with pulse detection. Not available with MCP23017
3	Inverted with pulse detection. Not available with MCP23017

The binary input filter "f" can be set to any integer value between 1 (soft) and 255 (hard) to avoid interference such as debounce from the input when a button pressed.

Button filter	Description
5	Default GPIO filter value (default)
1 to 255	Set filter value to avoid bounces and interferences. 1 is the softer value.

Modes 7 and 8. PWM Software options:

[ [ gpios ], mode, pull-up/down, initial value, PWM mode, PWM dithering ]

Initial value	Description
0	Set initial PWM output value to 0 (default)
0 to 65535	Initial PWM output value

By default, trailing mode is used. But some hardware may require to use leading, like TRIACs. This array will specify which channels must be leading:

PWM Mode	Description
0	Normal Trailing (default)
1	Inverted Trailing
2	Normal Leading
3	Inverted Leading

PWM Dithering	Description
0	No PWM Dithering (default)
0 to 32768	Deformation of PWM to avoid noises and armonic interferences.

Mode 10. ADC (Only ESP32)

[ [ gpios ], mode, pull-up/down, attenuation ]

Attenuation	Description
0	No input attenuation, ADC can measure up to approx (default)
1	The input voltage of ADC will be attenuated extending the range of measurement by about 2.5 dB (1.33 x)
2	The input voltage of ADC will be attenuated extending the range of measurement by about 6 dB (2 x)
3	The input voltage of ADC will be attenuated extending the range of measurement by about 11 dB (3.55 x)