Month March 2010

128 Is Not Enough

With more work, I was able to further squeeze the design down to 77 macrocells! You can grab the latest version of the Verilog files here.Unfortunately, when I then started to add the X register and its related functionality, things…

Classic 8-bit CPU chips

8-Bit CPU Comparison

BMOW’s instruction set was a close cousin to the 6502’s, and so when I started on CPLD CPU, I initially intended to try something different. I looked at the Intel 8008 and 8080, Zilog Z80, and Motorola 6800 and 6809,…

Black BMOW logo T-shirt

T-Shirts

BMOW logo T-shirts are now available! Check the link on the left sidebar. Get one and show a little electronics geek pride! Available in six colors, $18.99 each, operators are standing by to take your order. These are the same…

Feeds

If you’re not reading the BMOW comments, you’re missing half the discussion. Matthew Simmons asked if there’s a comments feed, and the answer is YES. I’ve added links for both the posts and comments feeds to the left sidebar. I…

ModelSim simulation waveforms

Birth of a CPU

I’ve finished the basic guts of the CPLD CPU, and it works! It’s still missing roughly half of the intended CPU functionality, but what’s there now is still a usable CPU. I’ve implemented jumps, conditional branching, set/clear of individual ALU…

Altera CPLD macrocell diagram

Separated at Birth

I’ve been planning to use an Altera Max 7128S for this CPLD – CPU project, because at 128 macrocells it’s the largest commonly-available CPLD that I could find in a PLCC package. Yesterday, however, I started wondering how the competition…

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