Logic chip cheatsheet
74xx04
The 74xx04 is a hex inverter.
Used in some MVS for the Battery-backed RAM, in the AES for the color burst oscillator and main system clock and also in the AES and some MVS for the Memory card interface.
Found in DILP-14 packages.
74xx32
The 74xx32 is a quad. 2-input OR gate.
Used in the MVS for the Battery-backed RAM and also in the AES and some MVS for the Memory card interface.
Found in DILP-14 and SOP-14 packages.
Memory card interface
- 3A: 74HC259 PIN 7
- 3Y: 74HC32 PIN 2
- 5A: 74HC32 PIN 12
- 5Y: NEO-G0 PIN 51
- 6A: CRDC
- 6Y: 74HC32 PIN 11
74xx05
The 74xx05 is a hex inverter.
Used in some MVS for the System ROM mapping circuit, and also in the AES and MVS for the Video DAC.
Found in DILP-14 and SOP-14 packages.
Memory card interface
- 1A: 74HC259 PIN 6
- 1B: 74HC04 PIN 6
- 1Y: 74HC32 2A
- 2A: 74HC32 1Y
- 2B: CRDW
- 2Y: Memory card connector PIN 15
- 3A: 74HC259 PIN 9
- 3B: Memory card Output enable
- 3Y: Memory card connector PIN 61
- 4A: nc
- 4B: nc
- 4Y: nc
74xx06
The 74LS06 is a hex inverter.
Used in the AES and some of the MVS for each of the player's OUT1, OUT2 and OUT3 controller ports.
Found in DILP-14 and SOP-14 packages.
74xx244
The 74xx244 is an octal 3-state buffer.
74xx273
The 74xx273 is an octal D-type flip-flop.
Used in the AES and MVS for the color bits.
Found in DILP-20 and SOP-20 packages.
