Sahithyan's S2 — Computer Organization And Digital Design
Logic Gates
There are AND, OR, XOR, and their inverted versions.
BUF
A logical gate that reflects the input as is. But there is a time delay.
Tri-state buffer
Works as a switch. A control signal. if the control signal is
- 0 - disconnected
- 1 - connected
Extending for n-inputs
XOR
Returns true iff when the number of true inputs are odd.
Logical circuit representation
Logical circuits are a abstraction of transistor circuits. The circuits can be built using TTL or CMOS.
TTL
Two or more transistors are used.
CMOS
Uses 2 metal oxide semiconductors.
Power consumption
Here:
- Capacitance of the circuit - Supply voltage - Charging frequency of the capacitor
Here:
- Supply voltage - Leakage current
Logic circuits
| Combinational | Sequential | |
|---|---|---|
| Memory | No | Yes |
| Feedback loop | No | Yes |
| Output | Depends on input | Depends on input & memory |