Micropython, CardComputer - issue reading Keyboard
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Hi, I've sucessfully installed the most recent ESP32S3 build of Micropython on my M5Stack CardComputer. Due to it being a generic build, there are no specific device drivers included with the firmware; however, I've managed to get some integrated peripherals working, ie the LCD, sdCard.
The keyboard (schematic) in giving me some problems, its a pretty standard key matrix, the rows are provides using a 74hc138 3-8 line decoder, and the columns are 7 GPIOs. The outputs from the decoder are active low (datasheet), so I made the column pins inputs with pullups - doesnt work, needs pulldowns????
Reading the column pins whilst iterating through the 8 rows should allow the individual key detection, but although key presses yield a pin change it doesn't work as expected and column 2 is always high???from time import sleep_ms from machine import Pin ''' M5Stack CardComputer Keyboard 74HC138 3 to 8 line decoder Decoder Pin A2, A1, A0 ----\ Y6, Y5, Y4, Y3, Y2, Y1, Y0 GPIO Pin G11, G9, G8 ----/ G7, G6, G5, G4, G3, G15, G13 ''' class KeyBoard(): def __init__(self): keyPins = [ ('C0', 13, Pin.IN, Pin.PULL_DOWN), ('C1', 15, Pin.IN, Pin.PULL_DOWN), ('C2', 3, Pin.IN, Pin.PULL_DOWN), ('C3', 4, Pin.IN, Pin.PULL_DOWN), ('C4', 5, Pin.IN, Pin.PULL_DOWN), ('C5', 6, Pin.IN, Pin.PULL_DOWN), ('C6', 7, Pin.IN, Pin.PULL_DOWN), ('A0', 8, Pin.OUT, None), ('A1', 9, Pin.OUT, None), ('A2', 11, Pin.OUT, None) ] ap = dict() for (name, pin, direction, pull) in keyPins: self.pinMap[name] = Pin(pin, direction, pull) def scan(self): for row in range(0,8): self.pinMap['A0'].value( row & 0b001 ) self.pinMap['A1'].value( row & 0b010 >> 1 ) self.pinMap['A2'].value( row & 0b100 >> 2 ) sleep_ms(250) print(f'{row:04b}\t',end='') for col in ['C0', 'C1', 'C2', 'C3', 'C4', 'C5', 'C6']: sleep_ms(0) val = self.pinMap[col].value() print(f'{val:01b} ', end='') print('') print('\n\n\n\n') keyboard = KeyBoard() while True: keyboard.scan() sleep_ms(500)Any ideas of where I'm going wrong??
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Hello @MartynW
I tried your code and changed two things to make it work:
- changed the inputs to pullups (as you already thought it should be) - the output matrix then is all 1s except for the button pressed.
- used some additional brackets for A1 and A2 to force the AND operation to happen first
self.pinMap['A0'].value( row & 0b001 ) self.pinMap['A1'].value( ( row & 0b010 ) >> 1 ) self.pinMap['A2'].value( ( row & 0b100 ) >> 2 )Full code:
from time import sleep_ms from machine import Pin class KeyBoard(): def __init__(self): keyPins = [ ('C0', 13, Pin.IN, Pin.PULL_UP), ('C1', 15, Pin.IN, Pin.PULL_UP), ('C2', 3, Pin.IN, Pin.PULL_UP), ('C3', 4, Pin.IN, Pin.PULL_UP), ('C4', 5, Pin.IN, Pin.PULL_UP), ('C5', 6, Pin.IN, Pin.PULL_UP), ('C6', 7, Pin.IN, Pin.PULL_UP), ('A0', 8, Pin.OUT, None), ('A1', 9, Pin.OUT, None), ('A2', 11, Pin.OUT, None) ] self.pinMap = dict() for (name, pin, direction, pull) in keyPins: self.pinMap[name] = Pin(pin, direction, pull) def scan(self): for row in range(0,8): self.pinMap['A0'].value( row & 0b001 ) self.pinMap['A1'].value( ( row & 0b010 ) >> 1 ) self.pinMap['A2'].value( ( row & 0b100 ) >> 2 ) sleep_ms(250) print(f'{row:04b}\t',end='') for col in ['C0', 'C1', 'C2', 'C3', 'C4', 'C5', 'C6']: sleep_ms(0) val = self.pinMap[col].value() print(f'{val:01b} ', end='') print('') print('\n\n\n\n') def scan2(self): for row in (7, 3, 6, 2, 5, 1, 4, 0): self.pinMap['A0'].value( row & 0b001 ) self.pinMap['A1'].value( ( row & 0b010 ) >> 1 ) self.pinMap['A2'].value( ( row & 0b100 ) >> 2 ) sleep_ms(250) print(f'{row:04b}\t',end='') for col in ['C0', 'C1', 'C2', 'C3', 'C4', 'C5', 'C6']: sleep_ms(0) val = self.pinMap[col].value() print(f'{val:01b} ', end='') print('') print('\n\n\n\n') keyboard = KeyBoard() while True: keyboard.scan() # keyboard.scan2() sleep_ms(500)BTW: I like your coding style with the pinMap etc. (Note: I am not very familiar with Micropython.)
Thanks
Felix
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Felix,
Thank you for the extra pair of eyes much appreciated, I got so obsessed with the PULL_UP/PULL_DOWN issue, I didn't even consider the processing order of the bitwise logic!! Many thanks.
Martyn
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Hello @martynw, I've been trying for a while to get my CardComputer's screen to work with Micropython code. I want to display a simple "hello world," but I'm having trouble. Could you help me? Could you show your code for activating the screen and writing anything on it?
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Hello MartynW
how do you use just the machine library. When I try this the m5stack gives an error.
When I use the m5stack lib I don't have any problems with this
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@felipeparaizo said in Micropython, CardComputer - issue reading Keyboard:
Hello @martynw, I've been trying for a while to get my CardComputer's screen to work with Micropython code. I want to display a simple "hello world," but I'm having trouble. Could you help me? Could you show your code for activating the screen and writing anything on it?
Have you added a driver to control the screen?
@thijsnl said in Micropython, CardComputer - issue reading Keyboard:
Hello MartynW
how do you use just the machine library. When I try this the m5stack gives an error.
When I use the m5stack lib I don't have any problems with thisWhat's is the error?
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@ajb2k3 said in Micropython, CardComputer - issue reading Keyboard:
Você adicionou um driver para controlar a tela?
Não, qual seria esse driver ? como posso adicionar ?
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@felipeparaizo said in Micropython, CardComputer - issue reading Keyboard:
Não, qual seria esse driver ? como posso adicionar ?
Você precisa fazer upload do driver Micropython para a tela ST7789V2 no micropython usando thonny.
