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Re: JTAG commands are secret?

2005-11-04 by tsvetanusunov

> 1. Sure, but JTAG is used (as standard) for testing only (with 
commands 
> BYPASS, IDCODE, EXTEST etc.).
> 2. I asked about Flash memory programming - not using SRAM as a 
program 
> memory.

they can't tell you JTAG commands for Flash memory programming for 
the simple reason that they don't exist :)

> 3. If you want to load some code to SRAM memory you should use 
special 
> commands (codes) for switching TAP into "SRAM load mode" (name of 
this mode 
> is my own, it is not possible to find them in official docs ;-)).

you are wrong, there is no SRAM load mode, but the "secret" is that 
you can execute ALL ARM7 instructions through the JTAG interface by 
putting them into the pipeline, so you execute this way small code 
which do writes to your SRAM the information you want to write to the 
flash (learn ARM assembler first for the data store commands ;) then 
small code which calls Flash write IAP and you are set
Best regards
Tsvetan
---
PCB prototypes for $26 at http://run.to/pcb 
(http://www.olimex.com/pcb)
PCB any volume assembly (http://www.olimex.com/pcb/protoa.html)
Development boards for ARM, AVR, PIC, MAXQ2000 and MSP430  
(http://www.olimex.com/dev)

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