fx2grok

The fx2grok family consists of four devices (fx2grok-flat, fx2grok-tiny, fx2grok-bga, fx2grok-wide) of very small, Open Hardware FX2-based logic analyzers.

The schematics and layouts are done from scratch in KiCad, and are released under the CC-BY-SA 4.0 license.

Using the open-source fx2lafw firmware (and sigrok, of course) you can use these devices as 8-channel (or 16-channel, for the fx2grok-wide) logic analyzers.

Device comparison

Note: All of this is work in progress and might change at any time!

Item	fx2grok-flat	fx2grok-tiny	fx2grok-bga	fxgrok-wide
Goals 2	Small Open Hardware Convenient and reliable to use in practice	Even smaller Open Hardware "Just for fun" project, doesn't have to be practical Sacrifices a lot of things for reduced size	Smallest-possible Open Hardware "Just for fun" project, doesn't have to be practical Sacrifices even more things for reduced size	Small, but 16 channels Open Hardware Reliable and convenient, with a few more channels
Author	Piotr Esden-Tempski	Uwe Hermann	Uwe Hermann	Ryan "Izzy" Bales, based off of Piotr Esden-Tempski's fx2grok-flat
Hardware license	CC-BY-SA 4.0	CC-BY-SA 4.0 1	CC-BY-SA 4.0	CC-BY-SA 4.0
Size	33 mm x 16 mm	11 mm x 11 mm	tbd	tbd
Logic channels	8 + CLK & TRIG	8	tbd	16
Layout specs	One sided load 4 layer PCB/layout 0.15 mm trace/space 0.3 mm drill & 0.1 mm annular ring	Double-sided 2-layer PCB/layout Components soldered on both sides 0.8 mm PCB thickness 5 mil traces, 6 mil trace clearance 8 mil via drill hole diameter, 5 mil annular ring	tbd	tbd
Cypress FX2	Cypress CY7C68013A-56LTXC, QFN, 8 mm x 8 mm	Cypress CY7C68013A-56LTXC, QFN, 8 mm x 8 mm	Cypress CY7C68013A-56BAXC, BGA, 5 mm x 5 mm	Cypress CY7C68013A-56LTXC, QFN, 8 mm x 8 mm
Input protection	3 x IP425x-4-TTL EMI/ESD filters on all probes + 100k pull-ups, 1x USBLC6-2 for USB	None whatsoever	None whatsoever	100Ω on each probe, 4x DSILC6-4 for all probes, 1x USBLC6-2 for USB
24 MHz crytal	ABM8	4-SMD, 300μW, 2 mm x 1.6 mm	tbd	tbd
USB connector	USB Micro-B SMD	USB Micro-B SMD	tbd	USB Micro-B SMD
Probe connector	2x6 1.27 mm PCB-edge connector	2x5 1.27 mm PCB-edge connector	tbd	2x 2x5 1.27 mm PCB-edge connectors
EEPROM	Yes, sigrok fx2lafw (8-channel) VID/PID 1d50:608c	None, default Cypress VID/PID 04b4:8613	None, default Cypress VID/PID 04b4:8613	Yes, sigrok fx2lafw (16-channel) VIP/PID 1d50:608d
Passives	Mostly 0402, some 0603 & 0.4 mm pitch DFN	Only 0402	tbd	Mostly 0402, some 0603
LED	1x 0603 LED on PA1	1x 0402 LED on PA1	tbd	1x 0603 LED on PA1

¹ The obsolete/nonworking fx2grok-tiny 0.1 was licensed CC-BY-SA 3.0, since version 0.2 the license is CC-BY-SA 4.0.
² Optional goal: Make a tiny 3D-printed enclosure, and/or an "enclosure" using resin (example) with the device (including probes) ideally looking similar to the sigrok logo in the end.

What is NOT the goal?

As you may know, there are tons of FX2-based logic analyzers (and tons of clones) already. There's not much use in creating yet another "standard" device.

The goal of this little hobby project is thus NOT to make a better device, or to make a cheaper device, or anything like that. The only goal is to have it as tiny as possible (it's more of a "just for fun" project).

Status

fx2grok-tiny 0.2 has been tested and is known to work. The first PCB version (fx2grok-tiny 0.1) is not working and thus obsolete.

Download

The schematics, PCB layout and Gerber files are available from the fx2grok Git repository:

$ git clone git://sigrok.org/fx2grok

Photos

Schematics, PCB layout, 3D preview

fx2grok-tiny 0.2:

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  Schematics

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  PCB layout

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  3D preview, top

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  3D preview, bottom

fx2grok-flat 0.2:

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  3D preview, top

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  3D preview, bottom

Cable and connector variants

Samtec SFSD-05-28-H-10.00-SR + TFM-105-01-L-D:

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  Samtec SFSD-05-28-H-10.00-SR

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  Connector with notch

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  Crimp parts

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  Crimp

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  Finished cable

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  Cable with probes

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  Samtec TFM-105-01-L-D

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  Samtec TFM-105-01-L-D

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  Cable connected

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  Cable + pinheader

Hand-soldered ribbon cable:

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  Ribbon cable

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  Individual wires

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  Soldered connector

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  Kapton tape

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  Finished cable

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  Cable comparison

Assembly

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  Size comparison

Bill of materials

fx2grok-tiny 0.2

Note: All prices are for single quantities, most parts get a lot cheaper if you buy higher quantities.

Qty	Device	Footprint	Size	Value	Refdes	Digikey	Mouser	Comments
Required parts
1	Cypress CY7C68013A-56LTXC	QFN-56	8 mm x 8 mm	—	IC1	10.05€	10.30€	Main chip. Alternatives: Future Electronics: 6.55€ eBay: 4.07€ Aliexpress: 1.52€ (10 pcs lot, 15.16€ total)
1	Amphenol FCI 10118192-0001LF	custom	9.8 mm x 5.6 mm	—	U1	0.38€	0.35€	USB Micro-B SMD connector
1	Murata XRCGB24M000FAN00R0	custom	2 mm x 1.6 mm	24 MHz	Y1	0.29€	0.46€	24MHz crystal, ±25ppm, 6pF, 150 Ohms, max. 300μW drive level, 4-SMD, no lead
1	Micrel MIC5504-3.3YM5-TR	SOT-23-5	2.9 mm x 1.6 mm	3.3 V	U2	0.10€	0.10€	3.3 V LDO, max. 300mA
4	Yageo RC0402JR-072R7L	0402	0.25 mm x 0.125 mm	2.7 kΩ	R2, R3, R4, R5	0.08€	0.08€	Resistor
1	Samsung RC1005J104CS	0402	0.25 mm x 0.125 mm	100 kΩ	R1	0.08€	—	Resistor
8	Samsung CL05A104KP5NNNC	0402	0.25 mm x 0.125 mm	100 nF	C2, C5, C7, C8, C10-C13	0.08€	—	Ceramic capacitor
3	Taiyo Yuden JMK105BJ105KV-F	0402	0.25 mm x 0.125 mm	1 µF	C1, C14, C16	0.08€	0.10€	Ceramic capacitor
2	Murata GRM155R61A225KE95D	0402	0.25 mm x 0.125 mm	2.2 µF	C3, C6	0.08€	0.08€	Ceramic capacitor
2	Samsung CL05C120JB5NNNC	0402	0.25 mm x 0.125 mm	12 pF	C4, C9	0.08	—	Ceramic capacitor
1	Vishay VLMB1500-GS08	0402	0.25 mm x 0.125 mm	—	D1	0.34€	0.51€	LED
Optional parts / variants
1	Amphenol FCI 20021111-00010T4LF	custom	—	—	P1/P2	0.53€	0.55€	5x2 through-hole pin header (1.27 mm pitch), could soldered to the PCB (5 pins per side)
1	Amphenol FCI 20021311-00010T4LF	custom	—	—	—	0.68€	0.69€	5x2 connector/receptacle (1.27 mm pitch), could be used for soldering the probe cable/wires
1	Samtec TFM-105-01-L-D	custom	—	—	P1/P2	0.53€	—	5x2 through-hole pin header (1.27 mm pitch) with a notch, soldered to the PCB (5 pins per side), match for the Samtec SFSD-05-28-H-10.00-SR cable below
1	Samtec SFSD-05-28-H-10.00-SR	custom	—	—	—	4.77€	—	Potential probe cable, needs some crimping

Note: C15 is missing and there is a C16, which is correct. C15 was removed and the numbering wasn't reset.

Resources

• Cypress FX2 overview page
• CY7C68013A, CY7C68014A, CY7C68015A, CY7C68016A datasheet (PDF)
• EZ-USB Technical Reference Manual (TRM) (PDF)
• AN15456 - Guide to a Successful EZ-USB FX2LP Hardware Design (PDF)
• esden's series of videos on the fx2grok-flat design (schematics, PCB, with background information and almost a KiCad tutorial)
• esden's GitHub repository with the KiCad project files for the fx2grok-flat (in the "flat" branch)
• Ryan's GitHub repository with the KiCad project files for the fx2grok-wide (in the "wide" branch)