Device Pinouts
Pin numbers for the 74-series logic chips and IO board used in circuit-schematics. All quad 2-input gate chips (74HCT00, 08, 32, 86) share the same pin layout — only the gate function differs.
Source: CSSE2010/CSSE7201 Device Pinouts and Symbols (Blackboard, v4). This is the whole parts list: every gate chip in it is 2-input (plus the hex inverter), so a design needing a 3-or-more-input gate has to be built up from 2-input ones. There is no 3-input AND/OR/NAND in the kit.
Power and ground
Power/ground connections are shown separately from gate pins on a schematic (see circuit-schematics): logic high/power uses a VCC symbol, logic low/ground uses a ground symbol.
Quad 2-input gates (74HCT00 / 08 / 32 / 86)
| Chip | Function | Gate A | Gate B | Gate C | Gate D | VCC | GND |
|---|---|---|---|---|---|---|---|
| 74HCT00 | Quad 2-input NAND | in 1,2 → out 3 | in 4,5 → out 6 | in 9,10 → out 8 | in 12,13 → out 11 | 14 | 7 |
| 74HCT08 | Quad 2-input AND | in 1,2 → out 3 | in 4,5 → out 6 | in 9,10 → out 8 | in 12,13 → out 11 | 14 | 7 |
| 74HCT32 | Quad 2-input OR | in 1,2 → out 3 | in 4,5 → out 6 | in 9,10 → out 8 | in 12,13 → out 11 | 14 | 7 |
| 74HCT86 | Quad 2-input XOR | in 1,2 → out 3 | in 4,5 → out 6 | in 9,10 → out 8 | in 12,13 → out 11 | 14 | 7 |
74HCT04 — Hex inverter
Six independent NOT gates. VCC = pin 14, GND = pin 7.
| Gate | A | B | C | D | E | F |
|---|---|---|---|---|---|---|
| in → out | 1→2 | 3→4 | 5→6 | 9→8 | 11→10 | 13→12 |
74HCT74 — Dual D-type flip-flop (14-pin)
| Pin | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Signal | CLR1 | D1 | CLK1 | SET1 | Q1 | \(\overline{Q1}\) | GND | \(\overline{Q2}\) | Q2 | SET2 | CLK2 | D2 | CLR2 | VCC |
Set and clear inputs can be omitted from the schematic if not needed.
74HCT157 — Quad 2-input multiplexer (16-pin)
| Pin | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Signal | SEL | A0 | B0 | Y0 | A1 | B1 | Y1 | GND | Y2 | B2 | A2 | Y3 | B3 | A3 | ENABLE | VCC |
74HCT175 — Quad D-type flip-flop (16-pin)
| Pin | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Signal | CLR | Q0 | \(\overline{Q0}\) | D0 | D1 | Q1 | \(\overline{Q1}\) | GND | CLK | Q2 | \(\overline{Q2}\) | D2 | D3 | Q3 | \(\overline{Q3}\) | VCC |
74HCT283 — 4-bit full adder (16-pin)
| Pin | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Signal | S1 | B1 | A1 | S0 | A0 | B0 | C0 | GND | C4 | S3 | B3 | A3 | S2 | A2 | B2 | VCC |
\(C0\) is the carry-in, \(C4\) the carry-out; \(A_i, B_i\) are the two 4-bit operands and \(S_i\) the 4-bit sum.
IO board
| Pins | Function |
|---|---|
| 1 | TX |
| 2 | RX |
| 3 | SSD cathode |
| 4 | SSD decimal point |
| 5–11 | SSD segments G to A |
| 12–15 | Buttons B3 to B0 |
| 16 | Logic probe |
| 17–24 | LEDs L0 to L7 |
| 25–32 | Switches S0 to S7 |
On a schematic the IO board is labelled IO1 (IO2 for a second board), with inputs using an input-style arrow and outputs an output-style arrow (see circuit-schematics). Use sensible signal names rather than the raw pin labels where possible.