Proxmark3 community

Research, development and trades concerning the powerful Proxmark3 device.

Remember; sharing is caring. Bring something back to the community.

"Learn the tools of the trade the hard way." +Fravia

You are not logged in.


Time changes and with it the technology
Proxmark3 @ discord

Users of this forum, please be aware that information stored on this site is not private.

#1 2011-10-31 20:19:47

Registered: 2010-01-08
Posts: 35

ISO15693 Glitches

I suspect, that changing the FPGA-Conf-Word produces glitches in the coil output. This glitches are between almost 0 and about 80uS and occur about 220us before a ISO15693 transmission (Reader->Tag). By chance this glitches sometimes look like a valid bit-time ans seem to confuse some VICCs (tags) - or at least they don't recover fast enough. 

I've included two scope traces. They both show the signal on the rectified receiver coil. The transmission (SOF, read-command, etc.. in 2of4-mode) starts at the center line.

I suspect line 250 in armsrc/iso15693.c:



a) can I read the ConfWord, and set it only when needed different?

b) at the moment the FPGA is set to FPGA_MAJOR_MODE_HF_READER_RX_XCORR when in receive or idle-but-coil-energized mode.
Can I instead put the FPGA in HF_READER_TX when idle (mean, when I don't send data via AT91C_BASE_SSC->SSC_THR ?)
This way the glitch will happen somewhere else - long before the read command is send.



Board footer

Powered by FluxBB