picoZ80 - RP2350 based drop-in Z80 CPU replacement with WiFi management interface. Cycle-accurate Z80 emulation using PIO for Sharp MZ-700 and other vintage computers.

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picoZ80 is a custom PCB that drops into any Z80 DIP-40 CPU socket, replacing the physical Z80 processor with an RP2350B microcontroller running cycle-accurate Z80 bus emulation via PIO state machines. Three PIO blocks handle address, data, and control signals simultaneously at full Z80 bus speed. An ESP32 co-processor provides WiFi, Bluetooth, SD card storage, and a browser-based management interface. The board supports 8MB PSRAM, 16MB Flash, ROM/RAM banking at 512-byte granularity, virtual device handlers, floppy and QuickDisk emulation, and machine personas for Sharp MZ-700, MZ-80A, MZ-800, and other vintage computers. Configuration is entirely JSON-driven with no recompilation required. OTA firmware updates, dual firmware partitions, and a seven-page web UI round out the feature set.