HP Forum Archive 21

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JTAG on HP-12C and HP-15C LE Message #1 Posted by Ingo on 1 July 2013, 3:56 p.m. I'm wondering if anyone tried to read out the mem of the HP-12C or HP-15C LE via the 6pin JTAG (I assume) adapter that is located beten the two battery cells.? This could be a semi-convenient way to load and store programs.

Re: JTAG on HP-12C and HP-15C LE Message #2 Posted by Marcus von Cube, Germany on 1 July 2013, 5:03 p.m., in response to message #1 by Ingo You can't! The connector is a custom serial interface. In order to read out the flash memory you'll need to put the chip in a special SAM-BA boot mode. This can only be done by clearing flash memory which means you are loosing the firmware. Even with the boot bit set correctly, RAM cannot be easily accessed because it's being overwritten by the download software and/or lost by resetting the device.

Re: JTAG on HP-12C and HP-15C LE Message #3 Posted by Ingo on 1 July 2013, 5:09 p.m., in response to message #2 by Marcus von Cube, Germany What a pity! Thanks for enlightening me :) I was just curiouos, as the Atmel Datasheet says that the JTAG Interface supports Flash read via JTAG, and the 6pin header looked to me like exactly that. Edited: 1 July 2013, 5:24 p.m.

Re: JTAG on HP-12C and HP-15C LE Message #4 Posted by Harald on 1 July 2013, 5:44 p.m., in response to message #3 by Ingo I haven't opened up the 15C LE, but maybe it has the same option to be fitted with a JTAG as the 30B has. But even then you would probably need the software in order to create a memory map.

Re: JTAG on HP-12C and HP-15C LE Message #5 Posted by Katie Wasserman on 1 July 2013, 6:15 p.m., in response to message #4 by Harald There's no JTAG interface in the 15LE (and 12C+) Even if there were it would have the same issue as Marcus described.

Re: JTAG on HP-12C and HP-15C LE Message #6 Posted by Paul Dale on 1 July 2013, 6:37 p.m., in response to message #1 by Ingo More interesting would be to port Eric's nonpareil to the hardware so that the bugs can be fixed. - Pauli

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