719 ISC77x16
719 : ISC77x16
- Author: Hans Kristensen
- Description: 7 segment side scrolling display with 16 character programmeable message
- GitHub repository
- Open in 3D viewer
- Clock: 50000000 Hz
How it works
The chip implements a side scrolling 7 segment display, featuring an internal programmeable memory that can store a sequence of 16 alphanumeric characters. The 7 segment display constantly cycles through the stored 16 characters, and the stored characters are updated using connected switches.
How to test
Start by setting the register-select switches to program the desired memory spot, then set the character encoding switches to represent the desired character, last, toggle the regpush switch front and back to load the character into the memory. This is done to an arbitrary amount of the memory spots to create a message:)
The binary coding for the alphanumeric characters: +-----------+--------+-----------+--------+-----------+--------+-----------+--------+ | character | binary | character | binary | character | binary | character | binary | +-----------+--------+-----------+--------+-----------+--------+-----------+--------+ | (blank) | 0 | 8 | 8 | G | 16 | O | 24 | | 1 | 1 | 9 | 9 | H | 17 | P | 25 | | 2 | 2 | A | 10 | I | 18 | R | 26 | | 3 | 3 | B | 11 | J | 19 | T | 27 | | 4 | 4 | C | 12 | K | 20 | U | 28 | | 5 | 5 | D | 13 | L | 21 | V | 29 | | 6 | 6 | E | 14 | M | 22 | Y | 30 | | 7 | 7 | F | 15 | N | 23 | ? | 31 | +-----------+--------+-----------+--------+-----------+--------+-----------+--------+
External hardware
You will need an external board with an extra 7 segment display to get full functionality.
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | bit0 of the alphanumeric character to be programmed | Segment of the first 7 segment display | bit3 of the register selector |
| 1 | bit1 of the alphanumeric character to be programmed | Segment of the first 7 segment display | The write switch. Loads the alphanumeric character to the selected register when high |
| 2 | bit2 of the alphanumeric character to be programmed | Segment of the first 7 segment display | Segment of the second 7 segment display |
| 3 | bit3 of the alphanumeric character to be programmed | Segment of the first 7 segment display | Segment of the second 7 segment display |
| 4 | bit4 of the alphanumeric character to be programmed | Segment of the first 7 segment display | Segment of the second 7 segment display |
| 5 | bit0 of the register selector | Segment of the first 7 segment display | Segment of the second 7 segment display |
| 6 | bit1 of the register selector | Segment of the first 7 segment display | Segment of the second 7 segment display |
| 7 | bit2 of the register selector | Segment of the second 7 segment display | Segment of the second 7 segment display |