fx2grok

The fx2grok family consists of three devices (fx2grok-flat, fx2grok-tiny, fx2grok-bga) 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 3.0 or CC-BY-SA 4.0 license.

Using the open-source fx2lafw firmware (and sigrok, of course) you can use these devices as 8-channel 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
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
Author	Piotr Esden-Tempski	Uwe Hermann	Uwe Hermann
Hardware license	CC-BY-SA 4.0	CC-BY-SA 3.0 1	CC-BY-SA 4.0
Size	tbd	13mm x 13mm	tbd
Logic channels	8	8	tbd
Layout specs	Components only soldered on one side tbd	Double-sided 2-layer PCB/layout Components soldered on both sides 0.8mm PCB thickness 5mil traces, 6mil trace clearance 8mil via drill hole diameter, 5mil annular ring	tbd
Cypress FX2	Cypress CY7C68013A-56LTXC, QFN, 8mm x 8mm	Cypress CY7C68013A-56LTXC, QFN, 8mm x 8mm	Cypress CY7C68013A-56BAXC, BGA, 5mm x 5mm
Input protection	100Ω on each probe, 2x DSILC6-4 for all probes, 1x USBLC6-2 for USB	None whatsoever	None whatsoever
24MHz crytal	tbd	tbd	tbd
USB connector	USB Micro-B SMD	USB Micro-B SMD	tbd
Probe connector	2x5 1.27mm PCB-edge connector	2x5 1.27mm PCB-edge connector	tbd
EEPROM	Yes, sigrok fx2lafw (8-channel) VID/PID 1d50:608c	None, default Cypress VID/PID 04b4:8613	None, default Cypress VID/PID 04b4:8613
Passives	Mostly 0402, some 0603	Only 0402	tbd
LED	1x 0603 LED on PA0	1x 0402 LED on PA0	tbd

¹ Historical reasons.
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

Work in progress, untested, may or may not work!

The first PCB, fx2grok-tiny 0.1, has been found to be non-working. A fixed 0.2 version is currently being worked on.

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 0.1:

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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

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 0.1

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	8mm x 8mm	—	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	9.8mm x 5.6mm	—	U1	0.38€	0.35€	USB Micro-B SMD connector
1	Murata XRCGB24M000FAN00R0	custom	2mm x 1.6mm	24MHz	Y1	0.29€	0.46€	24MHz crystal
1	Micrel MIC5504-3.3YM5-TR	SOT-23-5	2.9mm x 1.6mm	3.3V	U2	0.10€	0.10€	3.3V LDO
4	Yageo RC0402JR-072R7L	0402	0.25mm x 0.125mm	2.7 kΩ	R2, R3, R4, R5	0.08€	0.08€	Resistor
1	Samsung RC1005J104CS	0402	0.25mm x 0.125mm	100 kΩ	R1	0.08€	—	Resistor
8	Samsung CL05A104KP5NNNC	0402	0.25mm x 0.125mm	100nF	C2, C5, C7, C8, C10-C13	0.08€	—	Ceramic capacitor
3	Taiyo Yuden JMK105BJ105KV-F	0402	0.25mm x 0.125mm	1uF	C1, C14, C16	0.08€	0.10€	Ceramic capacitor
2	Murata GRM155R61A225KE95D	0402	0.25mm x 0.125mm	2.2uF	C3, C6	0.08€	0.08€	Ceramic capacitor
2	Samsung CL05C120JB5NNNC	0402	0.25mm x 0.125mm	12pF	C4, C9	0.08	—	Ceramic capacitor
1	Vishay VLMB1500-GS08	0402	0.25mm x 0.125mm	—	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 (1.27mm pitch), could soldered to the PCB (5 pins per side)
1	Amphenol FCI 20021311-00010T4LF	custom	—	—	—	0.68€	0.69€	5x2 connector/receptacle (1.27mm 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 (1.27mm 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)