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1. niconiconi (niconiconi@cybre.space)'s status on Sunday, 18-Aug-2019 15:21:21 UTC niconiconi

   Fully assembled my #Z80 backplane!

   Nothing fancy for now, it's just a passive board with a USB power port, and a power-on reset button using the 555 timer as a Schmitt trigger inverter.

   Time to design the RAM/ROM board.

   #retrocomputing #electronics

   • ziggys likes this.
   • 🎓 Dr. Freemo :jpf: 🇳🇱 repeated this.
   • Bernie (codewiz@mstdn.io)'s status on Saturday, 24-Aug-2019 17:27:58 UTC Bernie

     @niconiconi The thing on the right must be the bus demultiplexer which was needed on Z80 and 8086...

     I never understood why they designed a multiplexed bus that differs from all RAM chips and requires an external chip with a latch wasting a clock on each access. Duh?

     #retrocomputing #electronics

   • Bernie (codewiz@mstdn.io)'s status on Saturday, 24-Aug-2019 17:30:44 UTC Bernie

     in reply to

     @niconiconi The 6502 and the 68000 could be connected to ram directly. And they were the awesomest 8bit and 16/32bit chips of the era.

     Amiga rulez!

     #c64 #amiga #retrocomputing

   • Bernie (codewiz@mstdn.io)'s status on Saturday, 24-Aug-2019 17:40:43 UTC Bernie

     @niconiconi Mea culpa, that thing on the right was clearly not a latch and clearly not demuxing anything! 🤦♂️

   • Bernie (codewiz@mstdn.io)'s status on Saturday, 24-Aug-2019 17:42:07 UTC Bernie

     in reply to

     @niconiconi And the thing on the left is just for mapping the high bits of the address bus to the chipselects.

   • Bernie (codewiz@mstdn.io)'s status on Saturday, 24-Aug-2019 17:50:17 UTC Bernie

     @niconiconi That ATmega there is much more powerful than the main processor, lol 🙂

   • niconiconi (niconiconi@cybre.space)'s status on Sunday, 25-Aug-2019 20:38:46 UTC niconiconi

     RAM board schematic is almost finished. Let's see if it's doable on a PCB, if not, the in-system programmer would be a separate board. #retrocomputing #electronics

     🎓 Dr. Freemo :jpf: 🇳🇱 repeated this.