Brad Linder
picoZ80 – A Z80 microprocessor drop-in replacement based on Raspberry Pi RP2350B and ESP32
The picoZ80 board is a drop-in replacement for the Z80 microprocessor based on the Raspberry Pi RP2350B dual-core Cortex-M33 microcontroller and an ESP32 wireless SoC for WiFi and Bluetooth connectivity. My first computer was a ZX81 powered by a Zilog Z80 microprocessor, which was eventually phased out in 2024 after almost 50 years of production. But retro computing enthusiasts keep the platform alive, usually with softcore FPGA implementations such as MiSTer. The picoZ80 is different as it relies on the programmable I/O (PIO) state machines from the RP2350B MCU to reproduce cycle-accurate address, data, and control buses of the Z80 MPU. picoZ80 specifications: MCU - Raspberry Pi RP2350B CPU – Dual-core Arm Cortex-M33 CPU @ up to 150/300 MHz (the two RISC-V cores do not appear to be used by the project) Memory – 520KB SRAM Storage – 8KB OTP flash Package – QFN-80 Memory - 8MB PSRAM Storage 16MB flash
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