This class provides the matrix keyboard interface.

Constructor

machine.KeyPad

class machine.KeyPad(row,col)

Parameter:

• row - Integer type. Row number. It shall be greater than 0 and cannot exceed the maximum value supported by the module.
• col - Integer type. Column number. It shall be greater than 0. The value cannot exceed the maximum value supported by the module.

If you do not set the row and column value, the default value is 4X4.

KeyPad Pin Correspondences:

When part of pins are used, you shall connect the keyboard and the pin according to row and column numbers in ascending order. For example, for EC600M, when a 2x2 matrix keyboard is used, the hardware will use 49, 51 and 48, 50 pins.

Example:

>>> # Creates a keypad object
>>> import machine
>>> keypad=machine.KeyPad(2,3)  # Sets a matrix keyboard with 2 rows and 3 columes
>>> keypad=machine.KeyPad()     # Default parameter. The default setting is a matrix keyboard with 4 rows and 4 columns
>>> keypad=machine.KeyPad(2)    # Sets the row value to 2. Default column Value. The default column value is 4. A matrix keyboard with 2 rows and 4 columes is initialized. 

Methods

keypad.init

keypad.init()

This method initializes keypad settings.

Return Value:

0 - Successful execution

-1 - Failed execution

keypad.set_callback

keypad.set_callback(usrFun)

This method sets callback function. After the external keyboard button is connected to the module, this callback function will be triggered when the external keyboard button is pressed and released.

Parameter:

• usrFun - Matrix keyboard callback function. Prototype:

  usrFun(result_list)
  

  Parameter of callback function:

  • result_list[0] : Key status (1 indicates the button is pressed and 0 indicates the button is released).

  • result_list[1] : Row number

  • result_list[2] : Column number

for example,the EC600M module, suppose the key connect pin 49 and pin 52,if press the key, the parameter of callback is [1,0,2],if release the key, the parameter of callback is [0,0,2].

Return Value:

0 - Successful execution

-1 - Failed execution

keypad.deinit

keypad.deinit()

This method deinitializes to release initialized resources and callback function settings.

Return Value:

0 - Successful execution

-1 - Failed execution

Example:

import machine
import utime
is_loop = 1
keypad=machine.KeyPad()  
keypad.init()
def userfun(l_list):
    global is_loop 
    if  l_list[0] != 1 :
        is_loop = 0
        print('will exit')
    print(l_list)
keypad.set_callback(userfun)
loop_num = 0
while is_loop == 1 and loop_num < 10:
    utime.sleep(5)
    loop_num = loop_num +1
    print(" running..... ",is_loop,loop_num)
keypad.deinit()
print('exit!')

WDT - Watchdog Timer

OneWire - One-Wire Protocol

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