All the schematics are almost finished, only the Control Logic Module is still in progress.
If you followed Ben videos you will probably find some differences. Most of the changes are due to IC stock or for future upgrades.
Here they are…
Clock Module
I added a power button with a NPN transistor and also modified the logic to reduce the number of IC from 3 to 2.
Program Counter Module
This program counter counts up to 255 ( 28 ) so longer programs can be added. Malvinos original design counts up to 15 ( 24 ).
Control Logic Module ( Instruction Register + Control )
Still working on it…
Memory Module ( Memory Address Register + RAM )
Instead of the 74189 that I couldn’t find I used the LY6264. It needs an additional transceiver that I forget to add to the schematic.
A.L.U. Module ( A Register + B Register + Arithmetic )
The design is the same as Ben but I’m thinking of adding 8 more signals to the Control Bus so for example I can add a B Register Out.
Output Module
Here an alternative to the 4bit register used previously. An 74xx273 with an 74xx08 to AND the EN with the CLK.
The EEPROM is an AT28C64, there is no stock of the 28C16.
I use EasyEDA for the design of the circuits. In some of the captures some components are highlighted in red, there is nothing to highlight, is a bug.
oFurafollas 