Implementation Technology
Standard Chips
- The 7400 series of chips are available in different types of logic gates
- Their function cannot be changed
Symbol for a 74x04 chip
Symbol for a 74x08 chip
Chips
| Configuration | AND | NAND | OR | NOR | XOR | XNOR |
|---|---|---|---|---|---|---|
| Quad 2 input | 74x08 | 74x00 | 74x32 | 74x02 | 74x86 | 74x7266 |
| Triple 3 input | 74x11 | 74x10 | 74x4075 | 74x27 | ||
| Dual 4 input | 74x21 | 74x20 | 74x4072 | 74x29 | ||
| Single 8 input | 74x30 | 74x4078 | 74x4078 |
Programmable Logic Devices
PLDs allow changing of logic, for example:
- Programmable logic arrays (PLA)
- AND gates and OR gates can be programmed
- Programmable array logic (PAL)
- AND gates can be programmed, OR gates are fixed
- Field-programmable gate arrays (FPGA)
- FPGAs include logic blocks (which can be programmed to behave like a gate), I/O pads for connecting the gates, and routing channels or wires/switches (think breadboard)