Hello
some news : We have now a working ARM core in debug. The problem is., as soon as TCK gets closcked, all the memories and peripherials are disconnected from the micro. (the nano freezes) I cannot acess any memory, so it's not possible to dump the mask rom. Also, between the clocking of the jtag, and the efffective stopping of the execution, many instruction can get executed, leading to random effects. These instructions are usually a fixed opcode. Useful infos we can get : - all core registers, at any time (small chance of corruption) - CP15 registers : R/W acess : config of the memory system... - some sparse data left in the data cache. Unfortunately the instruction cache cannot be acessed, and the caches are not active during the first phase of the boot (only activated when the screen light turns on) - the memory map is guessed to be nearly the same than the 8700 - the NOR flash is physically acessed, even if the value does not arrive to the processor. - i did not found a scanchain 3 (1 bit only ?) I suspect 2 things a) some protection scheme introduced by samsung externally to the core b) some problem from openocd for clocking the load instructions at system speed. For acessing the memory, the debugger needs to follow a special procedure, so that the core resynchronizes to sys. clock, instead of the JTAG clock. This could be an issue. Normally openocd handles this, but there are far more users of the ARM920 than the ARM940 (with different memory systems) To check that, we could make a trial with a commercial JTAG debugger+SW does someone here own this kind of hardware ? some data examples : http://f4eru.free.fr/nano2/log/ the dump with 4 words is the Dcache data the random patterns with most time 16bits content are the corrupt values Cory Walker a écrit : > Also, could you explain the difference between red and pink on your > annotations? > the pink is just for interesting signals... sto _______________________________________________ Linux4nano-dev mailing list [email protected] https://mail.gna.org/listinfo/linux4nano-dev http://www.linux4nano.org
