Fx2grok

The fx2grok device is intended to be the tinyiest possible Open Hardware FX2 eval board (that can be used as 8-channel logic analyzer).

The schematics and layout are done from scratch in Kicad, and are released under the CC-BY-SA 3.0 license.

Using the open-source fx2lafw firmware (and sigrok, of course) you can use this device as 8-channel logic analyzer.

Goal

• Make the tinyiest-possible FX2 eval board / logic analyzer.
• Optional: Make a tiny "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).

Hardware

• 13mm x 13mm PCB.
• Double-sided PCB/layout, 0402 SMD components soldered on both sides.
• USB micro-B connector.
• 1.27mm 5x2 pin header.
• FX2 in 56pin QFN package.
• Small SMD 24MHz crystal, or through-hole one with bent leads (less PCB space needed, but higher device).
• No buffer or other protection (not even 100 Ω resistors for each probe).
• No EEPROM, the device will enumerate with the standard Cypress FX2 "unconfigured device" USB VID/PID (04b4:8613).

Download

The schematics and PCB layout is available from the fx2grok git repository:

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

Bill of materials

Qty	Device	Footprint	Size	Value	Refdes	Digikey	Mouser	Comments
1	Cypress CY7C68013A-56LTXC	QFN-56	8mm x 8mm	—	IC1	11.33€	12.00€	Main chip. Alternatives: eBay: 4.04€ (but who knows if it's fake), Future Electronics: 5.52€
1	Hirose ZX62-B-5PA(11)	custom	9.8mm x 5.6mm	—	U1	0.98€	0.908€	USB Micro-B SMD connector
1	Abracon ABM11-24.000MHZ-B7G-T	custom	2mm x 1.6mm	24MHz	X1	2.27€	1.96€	24MHz crystal
1	Micrel MIC5319-3.3YD5	SOT-23-5	2.9mm x 1.6mm	3.3V	U2	1.89€	N/A	3.3V LDO
1	FCI 20021111-00010T4LF	custom	—	—	P1/P2	0.66€	0.42€	5x2 through-hole pin header (1.27mm pitch), soldered to the PCB (5 pins per side)
1	FCI 20021311-00010T4LF	custom	—	—	—	0.99€	0.49€	5x2 connector/receptacle (1.27mm pitch), used for the probe cable
5	Resistor	0402	0.25mm x 0.125mm	2.2 kΩ	...	...	...	...
1	Resistor	0402	0.25mm x 0.125mm	2.7 kΩ	...	...	...	...
1	Resistor	0402	0.25mm x 0.125mm	100 kΩ	...	...	...	...
9	Ceramic Capacitor	0402	0.25mm x 0.125mm	100nF	...	...	...	...
2	Ceramic Capacitor	0402	0.25mm x 0.125mm	1uF	...	0.071€	0.083€	...
3	Ceramic Capacitor	0402	0.25mm x 0.125mm	2.2uF	...	0.11€	0.066€	...
2	Ceramic Capacitor	0402	0.25mm x 0.125mm	12pF	...	...	...	...
1	LED	0402	0.25mm x 0.125mm	—	...	...	...	...

Resources

• Cypress FX2 overview page
• CY7C68013A, CY7C68014A, CY7C68015A, CY7C68016A datasheet (PDF)
• EZ-USB Technical Reference Manual (TRM) (PDF)
• AN15456 - Guide to Successful EZ-USB(R) FX2LP(TM) and EZ-USB FX1(TM) Hardware Design and Debug (PDF)