Library for QYF-TM1638 16 button display board, that works w/Raspberry Pi Pico

[zen375dragon]

I am unable to find a Micropython library for the QYF-TM1638 16 button display board. This version differs its other more common variant as it has 16 buttons instead of 8.

The 16 button version:

The 8 button version:

I had previously found libraries for this board however they were either written in Arduino or made to run via a Raspberry Pi Computer (NOT Rasperry Pi Pico).

I have the 8 button variant and its library is not compatible with this 16 button version.

Microcontroller: Raspberry Pi Pico
Board in subject: QYF-TM1638 16 button

[mcauser]

The 8 button version: https://github.com/mcauser/micropython-tm1638

[zen375dragon]

mcauser/micropython-tm1638#2

VojtechKlos had the same issue as mine in your repository. Have you been able to create the 16 button version yet?

[mcauser]

Now that I've found my QYF board, yes, I'll create a new driver to support it

[robhamerling]

Another version can be found here: https://gitlab.com/robhamerling/micropython-tm1638spi
This library currently supports only the board with 8 buttons. A minor change will be required to support boards with 16 buttons. The status of all buttons is in a 4 bytes buffer, by experimenting you may need to determine which bits support which buttons.

[mcauser]

Nice one. Looks like we have a lot of similar tm163x drivers 😄 I'll add yours to the Awesome MicroPython list

[zen375dragon]

Unfortunately I am not experienced enough with Micropython to adjust the driver.

@mcauser code:
https://github.com/mcauser/micropython-tm1638/blob/master/tm1638.py

    def _scan_keys(self):
        """Reads one of the four bytes representing which keys are pressed."""
        pressed = 0
        self.dio.init(Pin.IN, Pin.PULL_UP)
        for i in range(8):
            self.clk(0)
            if self.dio.value():
                pressed |= 1 << i
            self.clk(1)
        self.dio.init(Pin.OUT)
        return pressed

Could changing for i in range(8): to for i in range(16): be the first step in changing the code? I'm not sure if each button is wired the same way as the 8 button version. If they aren't, this probably won't work, and 4x4 scanning will need to be added, like in this video.

[mcauser]

I found my QFY-TM1638 board and LED&KEY boards.

On the QFY, _scan_keys() should still use range(8). The keys() method, however, is specific to the LED&KEY board button layout.

I'll add a new keys16() method, specifically for the QFY board, and test all of the other methods. Some are not relevant, such as the leds() method.

For now, if you fork the keys() method and print() the _scan_keys() values instead of adding to a single byte, it produces the following key map.

def keys16():
	tm.stb(0)
	tm._byte(66)
	for i in range(4):
		print(tm._scan_keys())
	tm.stb(1)

button	scan keys bytes
N/A	0,0,0,0
S1	4,0,0,0
S2	64,0,0,0
S3	0,4,0,0
S4	0,64,0,0
S5	0,0,4,0
S6	0,0,64,0
S7	0,0,0,4
S8	0,0,0,64
S9	2,0,0,0
S10	32,0,0,0
S11	0,2,0,0
S12	0,32,0,0
S13	0,0,2,0
S14	0,0,32,0
S15	0,0,0,2
S16	0,0,0,32

The layout it not as simple as the LED&KEY board. I'll massage those 4 bytes into a 16-bit value (0x0000-0xFFFF). ie.

S1 = 0x0001
S2 = 0x0002
S3 = 0x0004
S16 = 0x8000

Added new method qyf_keys() to my driver:
https://github.com/mcauser/micropython-tm1638/blob/master/tm1638.py#L183
It returns a 16-bit value, where each bit represents a button, SW1 = LSB

[mcauser]

It looks like the 7-segment is wired up differently too. I'll have to fork my driver to support both, or make a common ancestor.

eg1. Draw an "8." on the 7th (right most) digit:

QYF-TM1638 module
tm.write(b'\x01\x00\x01\x00\x01\x00\x01\x00\x01\x00\x01\x00\x01\x00\x01\x00')

LED&KEY module
tm.write(b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\x00')

eg2. Draw an "8." on the 1st (left most) digit:

QYF-TM1638 module
tm.write(b'\x80\x00\x80\x00\x80\x00\x80\x00\x80\x00\x80\x00\x80\x00\x80\x00')

LED&KEY module
tm.write(b'\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')

(7-seg bits are rotated)

[mcauser]

... because the LED&KEY and QYF boards have different quad 7-segment types and are thus wired differently.
LED&KEY uses 3641AH-6 8P which is common cathode.
QYF uses 3461BS which is common anode.