On-chip security method and apparatus

A method for delivering program code to a first computing device by a second computing device, the first computing device comprising a serial port, an internal read-only memory, and a FLASH memory, the method comprising:

• connecting a second computing device to the first computing device via the serial port;
• and
• at the first computing device, polling the serial port if a key value stored at a security location in the FLASH memory does not match a predetermined security value stored in the internal read-only memory, and downloading the program code through the serial port in response to a detection of serial port activity,
• wherein each of the key value and the predetermined security value is independent of other content stored in the FLASH memory.

An apparatus for use in a computing device, the computing device comprising a serial port, the apparatus comprising:

• a first memory for storing a key value in a security location;
• a second memory for storing a predetermined security value in a plurality of memory locations;
• a processor configured to:
• communicate with the first memory, second memory, and serial port;
• read the key value from the first memory and the predetermined security value from the second memory;
• compare the key value and the predetermined security value;
• and
• depending on the result of the comparison, either polling the serial port for activity or jumping to the first memory for execution of boot instructions stored therein,
• wherein the key value and the predetermined security value are independent of content stored in the first memory.