Universal 4x4 keypad
From ScienceZero
Contents
Keypads
3 predefined keypads and one user definable keypad. Selectable binary, ASCII or key number.
Telephone keypad
1 2 3 A 4 5 6 B 7 8 9 C * 0 # D
Calculator keypad
7 8 9 + 4 5 6 - 1 2 3 * 0 . E /
User defined keypad
7 8 9 / 4 5 6 * 1 2 3 - C 0 = +
Interface
- RS-232
- 16 to 43 478 Baud
- SPI
- 83 kHz with enable
- Parallel
- 4 bit parallel output of key number
- MIDI
Misc
- Selectable beep/LED
Pin assignment
- RB0-3 = Keyboard row output/Parallel data output
- RB4-7 = Keyboard column input
- RA0 = DATA (RS-232, SPI, MIDI)
- RA1 = CLOCK (SPI)
- RA2 = ENABLE (SPI, Parallel)
- RA3 = BEEPER/LED
- RA4 = Free
Connection diagram for keypad
If the keypad is 3 keys wide; leave RB7 disconnected.
RB0---X---X---X---X-- | | | | RB1---X---X---X---X-- | | | | RB2---X---X---X---X-- | | | | RB3---X---X---X---X-- | | | | RB4 RB5 RB6 RB7