This is a small daughter board that fits into the socket of the "Sally" custom CPU in the Atari 800XL, 65XE and 130XE microcomputers (the RF shield must be removed, otherwise the daugher board won't fit inside). It replaces that CPU with a CMOS, modern, low-power, fully static, currently in production W65C02S CPU and some auxiliary logic. The project has been featured in three videos in my YouTube channel ("The Byte Attic," https://www.youtube.com/channel/UCfzZNuoHys1t-AdwYDhOz8g). For more information and instructions, please peruse the "DOCUMENTATION" file. This project is provided under a license. Check the "LICENSE" file to become acquainted with its terms. DISCLAIMER: Should you choose to use any of the files in this repository for any purpose whatsoever, you do so entirely at your own risk. I offer no guarantees, representations or warranties of any kind and disclaim all responsibility for any damage incurred as a direct or indirect result of such use.