ULX3S PCB

This is work-in-progress place for putting some wishes of a small (94x51 mm) FPGA board.

Instead of describing in written, it is better explained when drawn in kicad:

kicad ulx3s.pro

Schematics is mostly complete. PCB routing is not complete (about 50 routes missing).

3D preview

Features

Power: Switching voltage regulators

Low power: RTC clock wakeup, quartz and battery

USB: FTDI FT231XS (1Mbit JTAG and 3Mbit usbserial)

GPIO: All differential, PMOD-friendly

RAM: SDRAM

Flash: SPI flash chip for FPGA config

Storage: Micro-SD slot

LEDs: 16 (8 blink-LEDs, 2 USB leds)

Buttons: 6 (4 direction and 2 fire buttons)

Audio: 3.5 mm jack footprint

Video: GPDI connector with 3.3V-5V I2C bidirectional level shifter

Display: placeholder for 0.96-1.3" SPI OLED COLOR or B/W

WiFi+bluetooth: placeholder for ESP-32 (JTAG and serial over WiFi possible)

GPDI is General Purpose Differential Interface, Electrically LVDS, mostly TMDS tolerant female receptacle more-or-less compatible with digital monitors/TVs

Todo

Improve Power supply routing

2.54 mm external JTAG header