Dear support,
I found this document on TI wiki: http://processors.wiki.ti.com/index.php/Emulation_Resets
In this document, the cpu reset is described as:
CPU Reset – Typically isolated to reset just the core, not the entire device. In multi-core devices typically isolated to a single core. In devices that support a software reset, a CCS Reset may be equivalent.
For C64x+ cores a CCS CPU Reset effects:
- Local CPU reset
- CPU control registers reset
- L1/L2 caches invalidated
- Outstanding read/write commands completed and are discarded by the CPU.
- IDMA reset
- Does not change memory configuration or control registers
- Does not touch clocks
- Does not corrupt memory
I have reasons to doubt the highlighted first point and let me explain why.
We are trying to implement a local reset from a host on the C6670.
We took, from a TI example a procedure to locally reset a core and this procedure is causing our host to stop working. We are investigating this issue.
What we know for sure is that when we run the reset from CCS, the host is happy and continues working.
What we know as well is that there is a register in the C6670, that will describe how the C6670 was reset.
@0x02620144 RESET_STAT See section 3.3.7 (see reference manual SPRS689D)
What this register say (since I cannot copy paste) is that if the MSB is on it is a global reset, if any of the 4 LSB is on, the respective core has run a local reset.
After a power on reset, the MSB is on which is what is expected.
When we run our local reset on each core after a POR, the 4 LSB's are on.
When we run the core reset from CCS, the MSB is still on, like nothing has happened. However, the core has jumped back to the BOOT_ADDRESS!!!!
We have tried for the last four week to stop the host from loosing it completely upon reset and we are running out of ideas. This process that should have been one of the simplest task in the implementation of our system is causing us a lot of delays.
Please, help me to understand what is CCS doing that I can apply the same procedure. Even if indeed, no reset is applied, how do CCS manage to bring the Core back to the BOOT_ADDRESS.
Lot of thanks in advance, best regards
Aymeric