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PICO9918

A drop-in replacement for the classic TMS9918A Video Display Processor (VDP) powered by the Raspberry Pi Pico (RP2040/RP2350) microcontroller.

The PICO9918 replaces the TMS9918 Family found in dozens of retro computers and game consoles from the late 1970s through the 1980s. The TMS9918A emulation is handled by the vrEmuTms9918 library, included as a submodule.

Key Features

• Drop-in 40-pin DIP replacement - no host modifications required for most systems
• VGA output - 640x480 @ 60Hz, 12-bit RGB (4096 colors)
• Digital A/V (HDMI) output via optional Digital AV Dongle
• SCART RGBs output - PAL 576i or NTSC 480i
• F18A compatibility - Enhanced VDP features including TMS9900 GPU emulation
• Configurable clock rate (252 / 302.4 / 352 MHz), scanlines, sprite limits, palettes and Diagnostic Overlays
• Native Configurator ROMs for TI-99/4A, ColecoVision and MSX
• Web-based configurator for all devices
• Dual-core architecture: Core 0 for TMS9918A emulation, Core 1 for video output
• PIO-driven hardware-timed bus interface and clock generation
• Flash-based persistent configuration (survives firmware updates)
• Tested and confirmed working on 40+ retro systems

Wiki Contents

Getting Started

• Firmware - Installation, updates, output modes and F18A compatibility
• Configurator - Native and web-based configuration tools
• Diagnostic Overlays - On-screen debugging and performance information

Hardware

• Hardware - Hardware variants and PCB revision history
• Digital AV Dongle - HDMI dongle for video and audio output
• Hardware Setup - FFC connector, jumpers and pin configuration
• TI-99 4A No-Cut Mod - No-cut installation mod for the TI-99/4A

Supported Devices

• Supported Devices - Overview of all compatible systems
• ColecoVision - ColecoVision, Coleco ADAM, CV-NUC+, Dina
• Texas Instruments TI-99 - TI-99/4, TI-99/4A, TI-99/4QI, TI-99/22
• MSX - Casio, Gradiente, National, Sharp, Sony, Toshiba, Yamaha MSX systems
• Sega SG-1000 - SG-1000, SG-1000 II, SC-3000
• NABU Personal Computer
• Memotech MTX
• Sord M5
• Tomy Tutor - Tomy Pyuuta, Tomy Tutor, Pyuuta Jr
• CreatiVision - VTech CreatiVision, Dick Smith Wizzard
• Powertran Cortex
• Homebrew Projects - HBC-56, TM990, Z80-Retro, Z80Ardu

Development

• Building from Source - Build instructions for firmware and configurator
• Firmware Architecture - Technical internals, PIO, DMA, memory layout
• F18A Programmers Reference - F18A enhanced registers, ECM, GPU, palette RAM
• SCART Output Reference - PAL/NTSC timing and voltage specifications

Purchasing

Fully assembled and tested PICO9918 PROs are available from:

• Tindie
• ArcadeShopper (North America)

Discussion

For the latest news and discussion, follow the AtariAge thread.

Videos

Video	Description
	First successful boot on a TI-99/4A
	Early prototype demo
	80 column mode test
	v0.4 integrated RP2040 single board
	F18A compatibility mode demo
	PICO9918 Configurator on ColecoVision

Licensing

• Firmware: MIT License
• Hardware: CERN-OHL-S v2 (Open Hardware Licence - Strongly Reciprocal)

Thanks

Special thanks to JasonACT (AtariAge) for hand-crafting the F18A mode's on-board TMS9900 "GPU" in ARM assembly and providing other valuable input to the project.