A Look at the 8-bit computer components.

Objectives

Notes

• Registers
  • Page
  • The video for this is here.
  • The 74x173
    • This is a 4 bit register.
    • 4 data inputs(D), 4 data outputs (Q)
    • M and N lines control output, both high = output
    • G1 and G2 control input, both low = read data
    • CLR clears the register
    • Clock
    • I think this chip is different from the data sheet, but matches Ben's diagrams.
  • The 74x245 is a 8-bit tri state device.
    • 16 data ports, 8 A, 8B
    • A direction indicator (DIR) (0 B->A, 1 A->B)
    • OE - output enable, low enables .
  • 
    • Note he ties G1 and G2 (enable not ) of both chips together to ground (pins 1 and 2).
    • He ties pins 9 and 10 (m and n, output control) together (yellow)
    • He ties the clock together (7 white)
    • The clear lines (15 yellow) are tied together as well.
    • The direction pin (1) on the tristate chip is tied to positive.
  • He then adds the wires connecting the chips
  • 
  • Finally he adds
    • 8 blue jumpers which he connects to the bus
    • A yellow enable line (left side) - drives output from tri-state
    • A yellow load line (left side)
    • A white clock line (Right side)
    • An orange reset line
  • 
  • In the digital file
    • The lines are not labeled the same
    • I set enable and load to be 1 by default.
    • My internal wires are the bus, but ...
  • 
  • A Digital Version
  • You can watch him test the registers here
  • The b register is the same.
  • The instruction register is a bit different.
    • He loads it from the bus.
    • But for output, he only sends the bottom 4 bits to the bus
  • At about 4:43 on the above video he hooks up two registers and transfers data.
  • He adds in the IR and at about 9:40 he executes a load 11 instruction!