fx2grok

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Revision as of 22:17, 16 September 2017 by Uwe Hermann (talk | contribs)
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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
  • 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 0402 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!

First PCB, fx2grok-tiny 0.1, is finished and test boards are ordered. Whether or not everything works as planned is yet to be seen.

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:

  • Schematics

  • PCB layout

  • 3D preview, top

  • 3D preview, bottom

Cable and connector variants

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

  • Samtec SFSD-05-28-H-10.00-SR

  • Connector with notch

  • Crimp parts

  • Crimp

  • Finished cable

  • Cable with probes

  • Samtec TFM-105-01-L-D

  • Samtec TFM-105-01-L-D

  • Cable connected

  • Cable + pinheader

Hand-soldered ribbon cable:

  • Ribbon cable

  • Individual wires

  • Soldered connector

  • Kapton tape

  • Finished cable

  • Cable 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:
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

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