USB analyser

USB analyser is aiming at using a Cypress FX2 together with sigrok and two 74HC595 to increase the sampling rate to 48 MHz.

PCBs have arrived!

Soldering started… FX2 to come next… BUG! LM1117 and LT1129 have different pinouts (both SOT-223 3.3V LDOs)… and I used a mixed one?!?

More bugs!

Here's a list of them with corrections:

Bug Description Corrective measure
3.3V LDO The pinout I used was a mixture between and Soldered twisted TO-92 version
USB pinout D+ and D- were swapped A special cable is the medium-term solution
595's /OE tied to VCC Mistake in the schematics… it's called “G” there and is connected wrongly IC pins lifed and tied to GND
FX2 reseverd pin floating pin was missing in my symbol (“who needs these reserved pins anyway!?!”) Pin tied to ground with wire

Here a few impressions:

USB decoding (finally!)

Now it works! Look at here! Well, at least in most cases. IMHO the timing in the decoder should be adjusted slightly.

S/PDIF decoding! Well, it's not what it is initally meant for, but for another project, I wanted to look at S/PDIF outputs. This is how one may record some two seconds of digital audio:

sigrok-cli --driver usbanalysser --samples=100M -P spdif:data=1 -A spdif=samples | grep Audio | awk '{printf("%06X\n",$2)}' |  xxd -r -p  | sox -t raw -r 48k -e signed -b 24 -c 2 -x - test.wav

using this simple set-up, consitsting essentially of a digital audio receiver (ORJ-8) connected (this Mac hast a TOSLINK output):


  • sigrok is what I used with its fx2lafw FX firmware and a modified driver to unmangle the bits
  • projects/electronics/usbanalyser.txt
  • Dernière modification: 2015/08/03 22:09
  • de magnustron