|
|
|
|
# ULX3S PCB
|
|
|
|
|
|
|
|
|
|
ULX3S = University digital Logic Learning Xtensible
|
|
|
|
|
board release 3 with SDRAM, Successor of
|
|
|
|
|
[ULX2S](http://github.com/emard/ulx2s).
|
|
|
|
|
|
|
|
|
|
3D preview
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
[Manual](/doc/MANUAL.md).
|
|
|
|
|
|
|
|
|
|
This is a small (94x51 mm) standalone FPGA board
|
|
|
|
|
for education, research and general purpose, with a full
|
|
|
|
|
featured selection of chips which I all wanted on
|
|
|
|
|
a low-cost PCB, but haven't found on the market.
|
|
|
|
|
It's open source and open hardware because if it is
|
|
|
|
|
good for our development of [f32c](http://github.com/f32c/f32c) SOC,
|
|
|
|
|
it should be also good to other projects.
|
|
|
|
|
|
|
|
|
|
ULX3S will carry all digital logic on our research, education and
|
|
|
|
|
makerspace projects in next 5 years.
|
|
|
|
|
|
|
|
|
|
ULX3S is standalone embeddable gadget with onboard display, buttons,
|
|
|
|
|
storage, WiFi and compatible connectors.
|
|
|
|
|
|
|
|
|
|
ULX3S can do things no other board can.
|
|
|
|
|
|
|
|
|
|
ULX3S can self-reflash with a bitstream sent
|
|
|
|
|
remotely from web interface over WiFi or from SD
|
|
|
|
|
card browsed by onboard OLED display and buttons.
|
|
|
|
|
|
|
|
|
|
ULX3S can completely power down and wakeup from
|
|
|
|
|
battery backed RTC.
|
|
|
|
|
|
|
|
|
|
ULX3S has rich range of chips and connectivity
|
|
|
|
|
required for many other open source projects:
|
|
|
|
|
SDRAM, USB, PS/2, SDCARD, HDMI, FLASH, RTC, I2C, OLED, AUDIO, ADC,
|
|
|
|
|
onboard FM/ASK antenna 88-433.92 MHz and 56 GPIO pins which
|
|
|
|
|
are all routed as differential pairs and have pinout that
|
|
|
|
|
is PMOD compatible.
|
|
|
|
|
|
|
|
|
|
ULX3S is sufficiently equipped to emulate
|
|
|
|
|
[Amiga](https://github.com/emard/Minimig_ECS) retro computer and
|
|
|
|
|
run its games, but can do much more.
|
|
|
|
|
|
|
|
|
|
[Schematics](/doc/schematics.pdf) and PCB are done in open source KiCAD 5 PCB editor:
|
|
|
|
|
|
|
|
|
|
kicad ulx3s.pro
|
|
|
|
|
|
|
|
|
|
[PCB v1.7](/pic/ulx3st-real.jpg) is produced. For this board to work,
|
|
|
|
|
IPC CLASS 3 quality PCB is required, 5/5 mil resolution and 0.2 mm holes.
|
|
|
|
|
Important board features are tested and work like
|
|
|
|
|
USB-JTAG, SDRAM, SDCARD, HDMI, FLASH, RTC, I2C, OLED, AUDIO, ADC, 433.92MHz
|
|
|
|
|
US2 can be used to plug USB-PS/2 combo keyboard but US2 feature as USB
|
|
|
|
|
host/device is not tested.
|
|
|
|
|
There are known issues, luckily most can be fixed by
|
|
|
|
|
[Upgrading PCB v1.7](/doc/pcb-v1.7-upgrade.md).
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
# Features
|
|
|
|
|
|
|
|
|
|
FPGA: Lattice ECP5 LFE5U-85F-6BG381C
|
|
|
|
|
|
|
|
|
|
USB: FTDI FT231XS (300kbit JTAG and 3Mbit USB-serial)
|
|
|
|
|
|
|
|
|
|
GPIO: 56 pins (28 differential pairs), PMOD-friendly
|
|
|
|
|
|
|
|
|
|
RAM: 32MB SDRAM MT48LC16M16
|
|
|
|
|
|
|
|
|
|
Flash: 4MB Quad-SPI Flash IS25LP032D for FPGA config
|
|
|
|
|
|
|
|
|
|
Storage: Micro-SD slot
|
|
|
|
|
|
|
|
|
|
LEDs: 11 (8 blink-LEDs, 2 USB LEDs, 1 WiFi LED)
|
|
|
|
|
|
|
|
|
|
Buttons: 7 (4 direction, 2 fire, 1 power button)
|
|
|
|
|
|
|
|
|
|
Audio: 3.5 mm jack with 4 contacts (analog stereo + digital audio or composite video)
|
|
|
|
|
|
|
|
|
|
Video: GPDI connector with 3.3V-5V I2C bidirectional level shifter
|
|
|
|
|
|
|
|
|
|
Display: placeholder for 0.96" SPI COLOR OLED
|
|
|
|
|
|
|
|
|
|
WiFi+bluetooth: placeholder for ESP-32 (Standalone JTAG web interface over WiFi)
|
|
|
|
|
|
|
|
|
|
ADC: 8 channels, 12 bit, 1 MSa/s MAX11125
|
|
|
|
|
|
|
|
|
|
Power: 3 Switching voltage regulators: 1.1V, 2.5V, 3.3V
|
|
|
|
|
|
|
|
|
|
Clock: 25 MHz onboard, external differential clock input
|
|
|
|
|
|
|
|
|
|
Low power sleep: RTC clock wakeup, power button, 32768 Hz quartz and battery
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
GPDI is General Purpose Differential Interface,
|
|
|
|
|
Electrically LVDS, mostly TMDS tolerant
|
|
|
|
|
female receptacle more-or-less compatible
|
|
|
|
|
with digital monitors/TVs
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
# Todo
|
|
|
|
|
|
|
|
|
|
Test the prototype.
|
|
|
|
|
|
|
|
|
|
[x] Silkscreen Double outline for BGA chip
|
|
|
|
|
[x] Silkscreen do not write over the solder pads
|
|
|
|
|
[x] Silkscreen JTAG signal names on 6-pin 2.54 mm header
|
|
|
|
|
[x] Silkscreen remove OLED outline
|
|
|
|
|
[x] Solder stop mask must go inbetween all SMD chip pads
|
|
|
|
|
[x] External differential clock input at J1_33 +/-
|
|
|
|
|
[x] physically sprinkle VCC blocator capacitors under BGA
|
|
|
|
|
[ ] Values on silkscreen
|
|
|
|
|
[x] Dedicated antenna pin
|
|
|
|
|
[x] onboard 433 antenna
|
|
|
|
|
[x] 433 remove GND and silkscreen test point
|
|
|
|
|
[x] Resistors for LEDs
|
|
|
|
|
[x] Move USB LEDs from bottom to top side
|
|
|
|
|
[x] Improve SDRAM routing - use VIAs for closest pins
|
|
|
|
|
[x] Increase thickness of power lines (5V, 3.3V, 2.5V)
|
|
|
|
|
[x] Compile a f32c bitstream using the schematics
|
|
|
|
|
[x] Compile differential GPDI output
|
|
|
|
|
[x] Connect more lines from ESP-32 to FPGA
|
|
|
|
|
[x] Connect FPGA USB D+/D- with 1.5k pullup in USB 1.1 (full speed) mode
|
|
|
|
|
[x] FPGA USB add 27 ohm + 3.6 V zener
|
|
|
|
|
[x] Symmetrically place USB connectors left-right
|
|
|
|
|
[x] External JTAG header
|
|
|
|
|
[x] Move JTAG 2 mm left
|
|
|
|
|
[x] Move WiFi Disable jumper closer to the BTN1 (angled header)
|
|
|
|
|
[x] Sprinkle 2.2uF capacitors on power lines
|
|
|
|
|
[x] Spice simulation of power-up/shutdown network
|
|
|
|
|
[x] 27ohm D+/D- to FT231XS
|
|
|
|
|
[x] DIP switch (4 switches)
|
|
|
|
|
[x] MAX11123 ADC SPI
|
|
|
|
|
[x] I2C for RTC
|
|
|
|
|
[x] main usb connector on top side
|
|
|
|
|
[x] space screw to other parts
|
|
|
|
|
[x] move battery away from screw hole
|
|
|
|
|
[x] top layer GND fill
|
|
|
|
|
[x] R25 move away from oled screw hole
|
|
|
|
|
[x] DIP switch to the right near RAM
|
|
|
|
|
[x] Move HDMI a bit closer to OLED
|
|
|
|
|
[x] 32768Hz oscillator footprint
|
|
|
|
|
[x] SD card footprint SCHD3A0100
|
|
|
|
|
[x] center the SD footprint for T&R
|
|
|
|
|
[x] SD connect GND (thin pins)
|
|
|
|
|
[x] move USB 0.5-1mm more out
|
|
|
|
|
[x] DIP SW footprint correct
|
|
|
|
|
[x] AUDIO jack footprint fits
|
|
|
|
|
[x] AUDIO jack pin 4 (ring2) connected to 4-bit DAC
|
|
|
|
|
[x] BTN footprint too small
|
|
|
|
|
[x] SMPS jumpers default OFF for prototype testing
|
|
|
|
|
[x] FPGA DONE to ESP-32
|
|
|
|
|
[x] Diodes manual soldering
|
|
|
|
|
[x] R56: FT231X rev A,B,C TXDEN to GND
|
|
|
|
|
workaround from TN140_FT231X Errata
|
|
|
|
|
[x] PCB for LFE5UM ready (some GND will change to
|
|
|
|
|
VCC for Serdes power supply, see LFE5U->LFE5UM
|
|
|
|
|
migration docs)
|
|
|
|
|
[x] Check GND/VCC for 45 and 85 packages,
|
|
|
|
|
for example pin T11 is NC on 25U, GND on 85U and VCC ond 85UM
|
|
|
|
|
[x] Reconnect WIFI_OFF so that jumper has priority
|
|
|
|
|
[x] 25MHz oscillator: needs clearance from LEDs, move under USB1
|
|
|
|
|
[x] connect SHUTDOWN to FPGA
|
|
|
|
|
[x] ESP-32: won't boot when SD connected. Don't solder it at PCB v1.7
|
|
|
|
|
It is routed differently in newer release
|
|
|
|
|
Arduino->Examples->ESP32->SD_MMC_Test
|
|
|
|
|
https://github.com/espressif/esp-idf/blob/master/examples/storage/sd_card/README.md
|
|
|
|
|
moved blue LED from GPIO2 to GPIO5
|
|
|
|
|
[x] I2C resistors increased 470->2.2k
|
|
|
|
|
[x] GPDI AC-coupling 100nF to each differential line.
|
|
|
|
|
[x] reliable shutdown (D11=RED LED, R4=4.7k)
|
|
|
|
|
[x] SDRAM raster back to 0.8 mm
|
|
|
|
|
[x] connect SPI Flash Quad Mode (QSPI)
|
|
|
|
|
[x] allow powering the board without powering FTDI chip
|
|
|
|
|
[ ] reverse D9 at US2 to draw power from usb instead of provide it
|
|
|
|
|
[x] micro USB extended pads for Handsoldering (already were extended)
|
|
|
|
|
[x] move 25MHz oscillator away from USB connector for handsoldering
|
|
|
|
|
[x] schematics gpio J..+- pins renamed to gp/gn for easier readability
|
|
|
|
|
[ ] route 16-channel ADC
|
|
|
|
|
[x] move 8 LEDs a bit down and right
|
|
|
|
|
[x] let SD_CLK go to FPGA clock capable pin: swap SD_CLK and SD_D2 pins
|
|
|
|
|
[x] additional 2 differential lines for US2
|
|
|
|
|
[x] additional US2 pins for pullup 1.5k
|
|
|
|
|
[x] additional US2 pins for pull up-down 15k
|
|
|
|
|
[x] unified US2 pullup/down: resistor-diode nework for pullup 1.5k and pulldown 15k
|
|
|
|
|
[x] clear silkscreen mess with Cx under FPGA
|
|
|
|
|
[x] power decoupling capacitors for ESP32 and OLED
|
|
|
|
|
[x] Connect switching power supply jumpers
|
|
|
|
|
[ ] every 1-2 seconds there are clicks at analog audio output
|
|
|
|
|
[x] 3.6V zener diodes must be on FPGA side
|
|
|
|
|
[x] can esp32 second tx/rx port make serial communication with FPGA
|
|
|
|
|
[x] Jumper to switch 2.5V/3.3V for left IO banks
|
|
|
|
|
[x] move usb pull from gpio bank0 to gpdi bank1
|
|
|
|
|
[x] isolate each PMOD group to each io bank
|
|
|
|
|
[ ] move GP7,GP8 from gpio bank0 to gpio bank7
|
|
|
|
|
[x] route selected voltage to VCCio0/7
|
|
|
|
|
[x] route selected voltage to J1 PMOD instead of 3.3V fixed
|
|
|
|
|
[x] more bank0,1,7 decoupling capacitors
|
|
|
|
|
[x] Move Jumper 2.5V/3.3V deeper inside PCB (angled header)
|
|
|
|
|
[x] 0R resistor placeholders to hardwire 2.5V/3.3V instead of the jumper
|
|
|
|
|
[x] Selected 2.5/3.3V to J1 header (instead fixed 3.3V)
|
|
|
|
|
[x] RTC battery capacitor
|
|
|
|
|
[x] battery + pad clearance
|
|
|
|
|
[x] PCB v1.8.1 redesigned to fit HDMI 649-10029449-111RLF (the cheapest)
|
|
|
|
|
[ ] use cheaper diodes 583-MM4148-T in SOD-80C package
|
|
|
|
|
[x] fix copper layer after using non-handsoldering resistor footprints
|
|
|
|
|
[x] DIP switch must be pulled up at 2.5/3.3V or 2.5V line, not 3.3V
|
|
|
|
|
[x] RTC time loss at power down fixed with 1k+22uF - see page 54 of datasheet
|
|
|
|
|
|
