Hello,
We are working with a custom board around the TMS570LC4357.
The board worked fined for quite some time, but after trying to launch a debug session from a linux workstation (CCS 6), we are no longer able to properly operate the board.
A short time after powering up the board, we can connect to the target just fine, but after a few seconds, the debugger disconnects from the target with the "unable to access the DAP" error message. We found out that if we cool the board, the time during which we have access to the processor is longer. We never managed to clear the flash during this time, CCS just crashes when we try to erase the flash and uniflash stops with an error message reporting that it's unable to read from address 0x08000000.
Using the AHB-AP we still have access to the system memory map. Through this interface we tried to perform a system reset using SYSECR register. The system reset is executed (update of the SYSESR), but we still cannot connect to the Cortex R5.
We noticed that after powering up the board we are able to access the debug APB bus (reading the debug ROM for instance), but it stops working after some time.
After power up the software is running (the EMIF has been configured, we can see the PC changing). After a system reset, the EMIF is not reinitialized.
We've checked all the power supplies to the processor and the OSCIN input.
We've read most of the threads on the forum regarding this issue without finding a solution, any help would be greatly appreciated.
In particular, is there a way to clear the flash using only the AHB-AP?
it would seem that the debug APB is locked somehow, any idea on what could trigger this?
Best regards,
Mathieu