Adding 3x4 example with no OLED

examples/tca8418_3x4_noOLED.py

@@ -0,0 +1,58 @@
+# SPDX-FileCopyrightText: Copyright (c) 2022 Liz Clark for Adafruit Industries
+#
+# SPDX-License-Identifier: Unlicense
+
+import time
+import board
+from adafruit_tca8418 import TCA8418
+
+i2c = board.I2C()  # uses board.SCL and board.SDA
+tca = TCA8418(i2c)
+
+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
+
+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 = event // 10
+            #  figure out column
+            col = event % 10
+            #  print event type first
+            if keyevent & 0x80:
+                print("Key down")
+            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)