Adding 3x4 OLED demo

Adding an example for the 3x4 numpad with an OLED to copy the Arduino lib example

Author: BlitzCityDIY

examples/tca8418_3x4_OLED.py

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+# SPDX-FileCopyrightText: Copyright (c) 2022 Liz Clark for Adafruit Industries
+#
+# SPDX-License-Identifier: Unlicense
+
+import time
+import board
+import displayio
+import terminalio
+from adafruit_display_text import label
+import adafruit_displayio_ssd1306
+from adafruit_tca8418 import TCA8418
+
+displayio.release_displays()
+
+oled_reset = board.D1
+
+i2c = board.I2C()  # uses board.SCL and board.SDA
+tca = TCA8418(i2c)
+display_bus = displayio.I2CDisplay(i2c, device_address=0x3D, reset=oled_reset)
+
+keymap = (('*', '0', '#'),
+          ('7', '8', '9'),
+          ('4', '5', '6'),
+          ('1', '2', '3'))
+
+# set up all R0-R2 pins and C0-C3 pins as keypads
+KEYPADPINS = (
+    TCA8418.R0,
+    TCA8418.R1,
+    TCA8418.R2,
+    TCA8418.C0,
+    TCA8418.C1,
+    TCA8418.C2,
+    TCA8418.C3,
+)
+
+# make them inputs with pullups
+for pin in KEYPADPINS:
+    tca.keypad_mode[pin] = True
+    # make sure the key pins generate FIFO events
+    tca.enable_int[pin] = True
+    # we will stick events into the FIFO queue
+    tca.event_mode_fifo[pin] = True
+
+# turn on INT output pin
+tca.key_intenable = True
+
+#  display width and height setup
+WIDTH = 128
+HEIGHT = 64
+BORDER = 5
+
+#  display setup
+display = adafruit_displayio_ssd1306.SSD1306(display_bus, width=WIDTH, height=HEIGHT)
+
+splash = displayio.Group()
+display.show(splash)
+
+# text area setup
+title_text = "TCA8418 Demo"
+title_area = label.Label(
+    terminalio.FONT, text=title_text, color=0xFFFFFF, x=10, y=10 // 2+1)
+splash.append(title_area)
+
+key_text = " "
+key_area = label.Label(
+    terminalio.FONT, text=key_text, color=0xFFFFFF, x=10, y=HEIGHT // 2+1)
+splash.append(key_area)
+
+while True:
+    if tca.key_int:
+        # first figure out how big the queue is
+        events = tca.events_count
+        # now print keyevent, row, column & key name
+        for _ in range(events):
+            keyevent = tca.next_event
+            #  strip keyevent
+            event = keyevent & 0x7F
+            event -= 1
+            #  figure out row
+            row = int(event / 10)
+            #  figure out column
+            col = event % 10
+            #  print event type first
+            if keyevent & 0x80:
+                print("Key down")
+                #  print each key pressed to display consecutively
+                key_area.text = key_area.text + keymap[col][row]
+            else:
+                print("Key up")
+            #  use row & column coordinates to print key name
+            print("Row %d, Column %d, Key %s" % (row, col, keymap[col][row]))
+        tca.key_int = True  # clear the IRQ by writing 1 to it
+        time.sleep(0.01)