fx2grok

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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 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 (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
  • 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 3.0 1 CC-BY-SA 4.0 CC-BY-SA 4.0
Size 33 mm x 16 mm 13 mm x 13 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 tbd 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 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:

fx2grok-flat 0.2:

Cable and connector variants

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

Hand-soldered ribbon cable:

Assembly

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 8 mm x 8 mm IC1 10.05€ 10.30€ Main chip. Alternatives:
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€ 24 MHz crystal
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
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.

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