Tom Kelliher, CS 240
Jan. 29, 2009
Read 2.1-2.
Binary logic, gates, Boolean algebra.
Block diagram of a PC, centered on system bus chip.
Include: keyboard, mouse, monitor, disk, CD, modem, network card, sound.
Terms (define): ISA, PCI, AGP, PCI-X, PCI Express, front side, etc. MHz, bandwidth, b, B, etc.
Why so many buses?
Why are computers digital?
What number system do they use?
Consider a circuit containing a power source, a resistor, and a capacitor, all in parallel.
How do we represent 0 and 1? Voltage. Or current.
Logic levels for SN7400 5 V part (see class home page for data sheet):
Example: 7400 two-input NAND gate waveform. Note voltage vs. time.
Why is digital logic binary?