Inventors:
Hugo Cheung - Tucson AZ, US
Lu Yuan - Tucson AZ, US
Terence Chiu - Tucson AZ, US
Bolanle Oladapo Onodipe - Fort Worth TX, US
Assignee:
Texas Instruments Incorporated - Dallas TX
International Classification:
G06F 7/04
US Classification:
726 17, 726 16, 726 26, 726 27, 713300, 713320
Abstract:
There are various methods of securing programs and data on a processor. The external address enable pin of the processor is sampled upon a power-on or reset to the processor, to determine whether or not accesses to external memory are allowed. Other changes to the external address enable pin are thereafter ignored. In addition, if it is determined that an internal memory access is occurring, the contents of such an access can be masked to prevent unauthorized viewing of the memory contents via an external memory bus. In addition, a programmable security bit may be set to disable the dumping of flash memory contents, allowing only the erasing of the flash memory.