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Projet 816wiki
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Project 816

A 16-bit microcomputer of today, built around a real W65C816S processor, the 16-bit version of the 6502, from the same family as the one in the Apple IIGS. Around it: two FPGAs, one soldered on the board for control, the other a module for video, a Raspberry Pi Pico 2 W for input and output, all on a Mini-ITX board. This wiki follows its design.

Start with Project 816 for complete beginners See where the project stands
  • 16-bita real W65C816S in native mode; about 6 MHz on average (estimate)
  • 16 MBof PSRAM, the 65816's whole address space, and no ROM: everything is loaded at start-up
  • 3programmable devices around the processor: two FPGAs and a Pico 2 W
  • Mini-ITXa 170 × 170 mm board that fits a standard PC case
Who does what in Project 816A real W65C816S shares its bus with three programmable devices: the system controller, a GW1NR-9 FPGA soldered on the board and bus master (clock, bank, decoding, sound, DMA), the Tang Nano 20K for HDMI video and the Pico 2 W for USB, the SD card, Wi-Fi and the clock. An expansion port completes the bus. The slaves expose only 32 registers each. The memory, 16 MB of QSPI PSRAM, and the 1.8 V audio codec are connected to the 9K alone.65816 busAudio codecTLV320AIC3254at 1.8 VI²S + I²C, bank 3W65C816Sthe 16-bit processor≈ 4 MHz expected“9K” controllerGW1NR-9 FPGA, solderedclock, bank, decoding,memory, sound, DMATang Nano 20KVERA-like videoHDMI output,video memory in its SDRAMPico 2 Winput/outputUSB, SD card,Wi-Fi, clockbus master32 registers32 registers16 MB PSRAM2 × APS6404L, no ROMconnected to the 9K aloneQSPIExpansion port2 × 25 header74LVC245 buffersA 3.3 V bus, with no level shifters; only the 9K's bank 3 runs at 1.8 V. Dots mark the taps on the bus.
Who does what: the processor shares its bus with three programmable devices; the memory is connected to the controller alone. The system controller, an FPGA soldered on the board, is the bus master; video and input/output only see a few registers.

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