The Ben Eater EEPROM Programmer, 28C256 and Software Data Protection
Many people are learning, like I did, about computer hardware by following Ben Eater’s 8-bit breadboard computer build. And many of those are either moving on to more advanced projects or using slightly different hardware for the build. And some of those are using larger EEPROM chips such as the 28C256. But there’s a catch …. Read More
Bentium Pro ALU: Overview, Registers, Adder, Logic, Shift/Rotate and Schematics
My Bentium Pro computer is a Ben Eater inspired machine which uses many of the same ideas and many identical or very similar circuits. My intention with these blog posts was to write about the things I have added or done differently and leave the same/similar stuff for people to copy from Ben. I also …. Read More
The Bentium Pro Flags Register
After giving you a general tour of the ALU of the Bentium Pro and the carry select circuitry I want to move onto describing the flags register and how the flags are evaluated. As a reminder, the Bentium Pro has four flags: Carry. This can contain the carry/borrow from the adder and also the bit …. Read More
Adding ADC, SBC, INC & DEC Operations To Ben Eater’s ALU
The ALU on Ben Eater’s original Bentium 8-bit computer has two operations: add (ADD) and subtract (SUB). This gives his design the ability to add and subtract 8-bit numbers. But if you want to add or subtract larger numbers then you need more than 8 bits. You could do this by expanding to a 16-bit …. Read More
My Breadboard ALU With Twenty Operations
Last year I built Ben Eater’s 8-bit breadboard computer, which taught me a lot about how processors work. But with only 16 bytes of memory it’s not really usable for any kind of real world tasks. As soon as I’d finished it I knew I wanted to make some upgrades. And when I looked at …. Read More