wirewizard
Newbie level 4
Hi,
i accidently locked the MAC7116 MCU on a board by trying to read the internal flash via JTAG. The unit locks itself down and gave me no further access via JTAG and also does not run it's application software anymore. There is also an external flash, but i guess it only contains supplemental software and the bootloader and stuff resides on the MAC internal flash.
MAC7100 Family devices implement a security feature that prevents the unauthorized read and write of the memory contents. This feature allows:
Protection of the contents of program Flash
Protection of the contents of data Flash
Operation in single-chip mode
Operation from external memory with internal program Flash and data Flash disabled
I've read a lot about this in the datasheets and other programmers configs but can make any progress to get it running again.
For now, my Segger J-Link supports this chip, but i can only read the CPU ID by JTAG and it seems to ignore all commands to hold the CPU or to access the registers or memory mapped IOs. Any attempt to issue a "Connect" result in an timeout waiting for the chip to reset and enter ICE.
The docs tell about a Jtag lockout recovery procedure, which involves mass erase internal flash, unsecure the device but i still have no clue how to do this? Every access to any memory location or whatever seems to imply a connection, which i can't start...
Help is needed... THX!
i accidently locked the MAC7116 MCU on a board by trying to read the internal flash via JTAG. The unit locks itself down and gave me no further access via JTAG and also does not run it's application software anymore. There is also an external flash, but i guess it only contains supplemental software and the bootloader and stuff resides on the MAC internal flash.
MAC7100 Family devices implement a security feature that prevents the unauthorized read and write of the memory contents. This feature allows:
Protection of the contents of program Flash
Protection of the contents of data Flash
Operation in single-chip mode
Operation from external memory with internal program Flash and data Flash disabled
I've read a lot about this in the datasheets and other programmers configs but can make any progress to get it running again.
For now, my Segger J-Link supports this chip, but i can only read the CPU ID by JTAG and it seems to ignore all commands to hold the CPU or to access the registers or memory mapped IOs. Any attempt to issue a "Connect" result in an timeout waiting for the chip to reset and enter ICE.
The docs tell about a Jtag lockout recovery procedure, which involves mass erase internal flash, unsecure the device but i still have no clue how to do this? Every access to any memory location or whatever seems to imply a connection, which i can't start...
Help is needed... THX!