Universal 4x4 keypad
From ScienceZero
Keypads
3 predefined keypads, one user definable. Selectable binary, ASCII or key number output.
Telephone Calculator User defined 1 2 3 A 7 8 9 + 7 8 9 / 4 5 6 B 4 5 6 - 4 5 6 * 7 8 9 C 1 2 3 * 1 2 3 - * 0 # D 0 . E / C 0 = +
Interface
- RS-232
- 16 to 43 478 Baud
- Data out and inverted data out for generating standard RS-232 voltages
- SPI
- 83.33 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 = Not connected
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