| atmega 328 | Function | LCD | Comments | |
| phy | log | |||
| 5V | Vdd | 1 | ||
| GND | Vss | 2 | ||
| Contrast in | 3 | Wiper of contrast pot | ||
| 14 | (dig8) | D0 | 4 | |
| 15 | (dig9) | D1 | 5 | |
| 16 | (dig10) | D2 | 6 | |
| 17 | (dig11) | D3 | 7 | |
| 6 | (dig4) | D4 | 8 | |
| 11 | (dig5) | D5 | 9 | |
| 12 | (dig6) | D6 | 10 | |
| 13 | (dig7) | D7 | 11 | |
| 23 | (alog0) | CSEL1 | 12 | |
| 24 | (alog1) | CSEL2 | 13 | |
| 1 | Reset | Reset | 14 | |
| 25 | (alog2) | R_W | 15 | read/write |
| 26 | (alog3) | D_I | 16 | data/instruction |
| 27 | (alog4) | EN | 17 | enable |
| Contrast out | 18 | 10k or 20k preset | ||
| A (4.2V) | 19 | |||
| GND | K (0V) | 20 | ||
| Port D | Port B | Port C | ||||||
|---|---|---|---|---|---|---|---|---|
| Physical | Logical | Function | Physical | Logical | Function | Physical | Logical | Function |
| 2 | 0 | d0 (RX) | 14 | 8 | d8 | 23 | 14 | a0 |
| 3 | 1 | d1 (TX) | 15 | 9 | d9 | 24 | 15 | a1 |
| 4 | 2 | d2 | 16 | 10 | d10 | 25 | 16 | a2 |
| 5 | 3 | d3 | 17 | 11 | d11 | 26 | 17 | a3 |
| 6 | 4 | d4 | 18 | 12 | d12 | 27 | 18 | a4 |
| 11 | 5 | d5 | 19 | 13 | d13 | 28 | 19 | a5 |
| 12 | 6 | d6 | ||||||
| 13 | 7 | d7 | ||||||
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Craig Leres