matsengI took a perfboard and soldered up power and the data/address busses of the MCU, SRAM, NVRAM and the address bus latch.
I did't really care about the exact order of the bits when wiring them up, I just went for the easiest layout. I'm not really sure why the manufacturers even care about designating the D0..D7 on a SRAM, the order is irrelevant as long as you don't move the chip to another system with live data on it. Same thing with the address bus. On a (EE)PROM it's required to carefully keep track of the A's and D's of course.
This is how it ended up:
Z8671 HEADER -------- ------ VCC P36 X2 P31 RW X1 P27 /E TX P26 a7 RX P25 6264 DS135 a6 /RES P24 ------- -------- a5 R/W P23 NC VCC A VCC a4 /DS P22 A /WE A /WE a3 /AS P21 A CS2 A A LS373 a2 P35 P20 A A A A ------- a1 GND P33 A a6 A a6 /OE VCC a0 P32 P34 a4 a7 a4 a7 a7 a6 d7 A8 d7 a5 /OE a5 /OE d7 d6 d6 A9 d6 a3 a2 a3 a2 d5 d4 d5 A10 d5 a0 /CS1 a0 /CE a5 a4 d4 A11 d4 a1 d7 a1 d7 a3 a2 d3 A12 d3 d5 d6 d5 d6 d3 d2 d2 A13 d2 d3 d4 d3 d4 d1 d0 d1 A14 d1 d1 d2 d1 d2 a1 a0 d0 A15 d0 GND d0 GND d0 GND LE GND
Only the front side is shown, the backside is a horrible mess of "roadrunner"-style point-to-point wiring using insulated magnet wire that I just soldered thru the insulation with a 400C soldering iron.
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What about a 573 instead of a 373 ? Too modern ?
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Well - yes actually... The 573 do have a proper and easy to work with pinout compared to the 373. What were the designers thinking when they did the 373? Following the same type of layout as the standard and/or/nand gates wasn't maybe the best of ideas of a bus-oriented latch...
I do have some junkboxes with ancient stuff in them, but no 573 in sight there and I really want to be using parts as true the the period as possible. I'm already a bit miffed over the fact that the AY-3-89xx is far to new to fit in with the rest of the parts... ;-)
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I suppose they were thinking "Oh DANG I don't have an extral metal layer to send this signal to the other side of the chip" :-/
Early ICs had only one metal layer, crossing wires was tedious and needed a pass in the (slow) diffusion layer...
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