Proxmark3 community

asper

Contributor

Registered: 2008-08-24

Posts: 1,409

Playing with JTAG

Just received a JTAG (probably clone); used SEGGER J-Flash ARM V4.50 version.

I followed the following steps:

01 - Plugged the Proxmark and the Segger J-LINK in to the computer
02 - Attached the J-LINK to the Proxmark JTAG port
03 - Opened J-Flash ARM V4.50 software
04 - Created a new project by selecting File > New project
05 - Changed the project settings by going to Options > Project settings
06 - Clicked on the Target Interface tab
07 - Changed the "JTAG speed before init" to 200 kHz
08 - Clicked on the CPU tab
09 - Selected the "Device" radio button and selected "Atmel AT91SAM7S256" from the drop-down list
10 - Changed the Clock speed to "Auto detection"
11 - Applyed the changes -> OK
12 - Tested connectivity to the Proxmark by selecting Target > Connect
13 - Target -> Read back -> Entire chip

I got the same dump as proxmark3_recovery.bin until offset 0x00032047 (in the SEGGER software interface the address is 0x132047)... what are the following dumped bytes (~56Kb) ? EEPROM bytes ?

Last edited by asper (2015-04-18 11:22:27)

iceman

Administrator

Registered: 2013-04-25

Posts: 9,538

Website

Re: Playing with JTAG

I got my chinese segger j-link today and followed your procedure.  Got the j-link to connect and read memory.
However the software was rev4.26,  and I couldn't write back the s19 files.  Strange, but I could erase all memory
and from there I just used the normal  flasher to flash bootrom and osimage.   Works like a charm again.   

Thanks!

Last edited by iceman (2015-06-02 13:28:50)

recrudesce

Member

Registered: 2015-06-01

Posts: 8

Re: Playing with JTAG

Can you tell me the pin layout you used ?  I wasn't able to get my BusPirate to talk via JTAG

iceman

Administrator

Registered: 2013-04-25

Posts: 9,538

Website

Re: Playing with JTAG

I got the flat cable, which fits onto a old pm3 perfect with the package.   
Did you read the wiki on pm3 and buspirate?

asper

Contributor

Registered: 2008-08-24

Posts: 1,409

Re: Playing with JTAG

Good iceman!
I did not test the write procedure. 4 50 should be included inside the cd-rom.