Tilda SNES controller

main.py

import pyb

#  SNES Connector pinout:
#
#   -----------------
#  | 1 2 3 4 | 5 6 7 >
#   -----------------
#
# 1 +5V    - Connect to vBAT
# 2 Clock  } Connect to any unused data pin and specify
# 3 Latch  } when creating the SNESpad object
# 4 Data   }
# 5 unused
# 6 unused
# 7 Ground - Connect to 0v

SNES_B=1<<0
SNES_Y=1<<1
SNES_SELECT=1<<2
SNES_START=1<<3
SNES_UP=1<<4
SNES_DOWN=1<<5
SNES_LEFT=1<<6
SNES_RIGHT=1<<7
SNES_A=1<<8
SNES_X=1<<9
SNES_L=1<<10
SNES_R=1<<11

class SNESpad:
        """Read buttons from SNES game controllers
        
        For a single controller the latch, clock and data pins must be specified.

        When using multiple controllers there is one data pin per controller 
        specified in a list. The latch and clock pins are shared.
    
        Usage:
        c = SNESpad(latch="X8", clock="X7", data=["X1", "X2", "X3", "X9"])
        print("Press some buttons on the controller")
        last=None
        while True:
            state = c.read()
            for i in range(len(state)):
                if last is None or state[i] != last[i]:
                    pressed = c.buttons(state[i])
                    print("Controller %d buttons: %s" % (i+1, pressed))
            last=list(state)
        """

        def __init__(self, latch, clock, data):
                self.pin_latch = pyb.Pin(latch, pyb.Pin.OUT_PP)
                self.pin_clock = pyb.Pin(clock, pyb.Pin.OUT_PP)
                self.pin_data = []
                if type(data) is str:
                    data = [ data ]
                for p in data:
                    self.pin_data.append(pyb.Pin(p, pyb.Pin.IN))
                self.data_count = len(self.pin_data)

        def read(self):
            # Latch current button state into buffer
            self.pin_latch.high()
            self.pin_latch.low()

            # Clear initial state for all data pins
            state = []
            for i in range(self.data_count):
                state.append(0)

            # Read 12 bits of button data
            for i in range(12):
                # Read button bit for each controller
                # Buttons are active low
                for j in range(self.data_count):
                    if not self.pin_data[j].value():
                        state[j] |= 1 << i

                # Clock in next button bit from buffer
                self.pin_clock.high()
                self.pin_clock.low()

            return state

        def buttons(self, state):
            # Decode the bitmap into a list of buttons
            pressed=[]
            if (state & SNES_A):
                pressed.append("A")
            if (state & SNES_B):
                pressed.append("B")
            if (state & SNES_X):
                pressed.append("X")
            if (state & SNES_Y):
                pressed.append("Y")
            if (state & SNES_L):
                pressed.append("L")
            if (state & SNES_R):
                pressed.append("R")
            if (state & SNES_SELECT):
                pressed.append("SELECT")
            if (state & SNES_START):
                pressed.append("START")
            if (state & SNES_UP):
                pressed.append("UP")
            if (state & SNES_DOWN):
                pressed.append("DOWN")
            if (state & SNES_LEFT):
                pressed.append("LEFT")
            if (state & SNES_RIGHT):
                pressed.append("RIGHT")
            return pressed

if __name__ == '__main__':
    c = SNESpad(latch="X8", clock="X7", data="X9")
    print("Press some buttons on the controller")
    last=None
    while True:
        state = c.read()
        for i in range(len(state)):
            if last is None or state[i] != last[i]:
                pressed = c.buttons(state[i])
                print("Controller %d buttons: %s" % (i+1, pressed))
        last=list(state)