liaminventions/sdcard6502

SD cards on a homebrew 6502 computer - tutorial guide and sample code

How to read and write SD cards with a 6502, step by step

This guide shows how to connect up an SD card reader to a Ben Eater style 6502 homebrew computer and use it to read/write data from SDHC cards.

The tutorial ends with being able to read arbitrary sectors from the SDHC card. Beyond that, I've included library-style code that can read/write from a FAT32 filesystem, with some example programs. For more information on this library code, see FAT32 Library Documentation

I'm only covering SDHC cards. You pretty much can't buy older/smaller cards these days, and not bothering to support the older protocol simplifies the code quite a bit.

Contents

Intro

• 0a Prerequisites and References
• 0b About the Sample Code
• 0c Initial Hardware Setup

Samples

• 1 Reading and Writing Bytes
• 2 Encaplusated sd_sendcommand
• 3 Complete Initialization Sequence
• 4 Reading Sectors

Appendices

• A Next Steps
• B Older SD/MMC Cards