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https://github.com/emard/ulx3s

PCB for ULX3S FPGA R&D board
https://github.com/emard/ulx3s

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PCB for ULX3S FPGA R&D board

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README 

        
# ULX3S PCB



[ULX3S](http://radiona.org/ulx3s) = [University digital Logic](https://www.fer.unizg.hr/en/course/diglog) Learning

Xtensible board release 3 with SDRAM,

Successor of [ULX2S](http://github.com/emard/ulx2s).



[Manual](/doc/MANUAL.md) *

[Quickstart Binaries](http://github.com/emard/ulx3s-bin) *

[ULX3S at Kitspace](https://kitspace.org/boards/github.com/emard/ulx3s)



3D preview



![TOP](/pic/ulx3st.jpg)

![BOTTOM](/pic/ulx3sb.jpg)



Prototypes available

at [SKRIPTARNICA](http://skriptarnica.hr/vijest.aspx?newsID=1466),

local shop inside of [FER](https://www.fer.unizg.hr/) university.



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](https://www.fer.unizg.hr/en/course/diglog) and

[makerspace](https://radiona.org) 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, Digital Video, FLASH, RTC, I2C, OLED, AUDIO, ADC,

onboard FM/ASK antenna 88-433.92 MHz and 56 GPIO pins routed as differential

pairs and have pinout that is PMOD compatible. There are 12 true

differential bidirectional pairs and 16 single-ended pairs.



ULX3S is sufficiently equipped to

emulate [Amiga](https://github.com/emard/Minimig_ECS) retro

computer and run its games, but can do much more like

running [Linux](https://twitter.com/fpga_dave/status/1053290842809683968).



[Schematics](/doc/schematics.pdf) and PCB started with KiCAD 4.

After version v1.8 project switched to KiCAD 5 PCB editor:



    kicad ulx3s.pro



View generated gerbers



    gerbv -p plot/ulx3s.gvp



# Features



FPGA: Lattice ECP5 [LFE5U-85F-6BG381C](http://www.latticesemi.com/view_document?document_id=50461) (12/25/45/85K LUT)



USB: FTDI [FT231XS](https://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT231X.pdf) (500kbit JTAG and 3Mbit USB-serial)



GPIO: 56 pins (12 true differential pairs, 16 single-ended pairs),

[PMOD](https://reference.digilentinc.com/_media/pmod:pmod:originalPmodInterfaceSpecification.pdf) compatible

with power out 3.3V/1A 2.5V/1.5A



RAM: 16-bit SDRAM [MT48LC32M16](https://www.micron.com/-/media/client/global/Documents/Products/Data%20Sheet/DRAM/256Mb_sdr.pdf) (8/16/32/64 MB)



Flash: Quad-SPI Flash [IS25LP128F](http://www.issi.com/WW/pdf/25LP-WP128F.pdf) (4/8/16 MB for FPGA config and user data)



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 [SSD1331](https://drive.google.com/file/d/0B5lkVYnewKTGRlpxcEdWaXNvWnM/view)



WiFi+bluetooth: placeholder for [ESP-32](https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf) (Standalone JTAG web interface over WiFi)



Antenna: 88-108/433 MHz FM/ASK onboard



ADC: 8 channels, 12 bit, 1 MSa/s [MAX11125](https://datasheets.maximintegrated.com/en/ds/MAX11120-MAX11128.pdf) (4/8-ch, 8/10/12-bit, 0.5/1 MSa/s)



Power: 3 Switching voltage regulators: 1.1V, 2.5V, 3.3V (1.5/2A)



Clock: 25 MHz onboard, external differential clock input



Low power sleep: 5uA/5V standby, RTC [MCP7940N](http://ww1.microchip.com/downloads/en/DeviceDoc/20005010F.pdf) 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



# Production



Independent production

like [q3k](https://twitter.com/q3k/status/1029010026269167618) or

[samlittlewood](https://twitter.com/samlittlewood/status/1108531208001077250) is

welcome and desirable under conditions of [modified MIT LICENSE](/LICENSE.md).

If you do manual assembly here is [minimal parts list](/doc/MINIMAL.md).



ZIP the gerbers and send them to manufacturer:



    zip -r /tmp/ulx3s.zip plot/ulx3s



If you are going to order this project by yourself, it is important

what manufacturer to choose for PCBA (PCB and Assembly) service.



Parts can be ordered from [Detailed BOM](/doc/ulx3s_bom.csv)

or from [ULX3S at Kitspace](https://kitspace.org/boards/github.com/emard/ulx3s),

which automatically submits [Simplified 1-click BOM](/1-click-bom.tsv) by

clicking on "Digikey" or "Mouser" button. On each click, Digikey and Mouser will keep

accumulating the BOM in the shopping cart. Number of unique parts on Digikey and Mouser

should be equal but DigiKey may split some parts (LEDs) in multiple rows.

To reset shopping cart, click "New Cart" or "New Basket".

Kitspace may be updated with about 1 day delay after this project update.



Choose PCBA manufacturer which can produce PCB of IPC CLASS 3 quality,

5/5 mil trace resolution and 0.2 mm holes.

Avoid manufacturer who claims "quality" and "satisfaction" but doesn't

really know what will be IPC CLASS rating for this project.



PCBA manufacturer prices for the parts should be approximately equal as those

from distributors like [Mouser](http://www.mouser.com) or [DigiKey](http://www.digikey.com).

Avoid any PCBA manufacturer who asks 3$ for the 1$ part or 40$ for the 30$ part.

Select [Mouser](http://www.mouser.com) language/location icon to PCBA manufacturer

country of origin and $-currency to check is PCBA manufacturer telling the truth

about prices.



Before soldering the parts, ask manufacturer for [pictures](/pic/ulx3sb-v18.jpg) of PCB.

CLASS 3 demands, among other things, that all drill holes stay inside of VIA pads.

If some holes [break-out](/pic/ulx3sb-v18-breakout-c19.png) from pads,

ask manufacturer to make new PCBs with better drill and copper layer alignment.



[PCBCART](http://www.pcbcart.com) offers CLASS 3 quality and assembly at reasonable cost.

Prices for the parts are equal to [Mouser](http://www.mouser.com).



Don't pay everything at once. Following payment phases during the

PCBA production are recommended:



    1. Pay for the parts

    2. Manufacturer orders the parts and optionally negotiates with you about part numbers.

       Depending on market availability, some parts may come in different physical package.

    3. Send updated gerbers which fit to ordered parts.

    4. Pay for PCB

    5. Manufacturer sends pictures of produced PCB for your inspection.

       If anything looks suspicious, ask also for X-ray imaging.

    6. Pay for the assembly and shipping.



Nobody wants quality issues, so it is good to ask if manufacturer has qualified personnel

able to follow instructions 

for [ULX3S self-test](https://github.com/emard/ulx3s-bin) before shipping.