W65C832 in an FPGA

CONTENTS YouTube BlueSky GitHub LinkedIn W65C832 In An FPGA Posted: October 16, 2024 Introduction Back in the 80's, the Western Design Center (WDC) created a 16 bit version of the 6502 CPU called the W65C816. I believe it was created for the Apple IIgs computer, although it was also used in the Super Nintendo. It appears they had a data sheet for a 32 bit version of the chip called the W65C832. I decided to do a Verilog version of it in an FPGA. I updated naken_asm so it has a .65832 directive that allows immediate values for things like lda and such to have a .l modifier so it can do 32 bit values now. The instruction set is able to access 16MB of RAM. The FPGA itself has a small amount of block RAM that this w65c832 core uses as 4k of RAM at the bottom of memory (for zero / direct page), 4k as ROM, and 4k as pages for a Winbond W25Q128J flash chip. More on that further on this page. The Verilog source code is available on GitHub and builds with the regu ... Read full article.