| ??? 02/26/08 16:12 Read: times |
#151487 - What if you don't bond out nPSEN? Responding to: ???'s previous message |
With 64KB of code space, there's really no way to determine, reliably, when the MCU is accessing code space, is there?
If you have no external memory, you have no need for that signal, and, with 64KB of on-chip FLASH, well, without it, it's pretty hard to figure out when various things are happening. Perhaps all it needs is to be able to disconnect the nPSEN signal from the pin, electronically, once the internal FLASH is programmed. Mightn't that be enough? RE |
| Topic | Author | Date |
| Obtaining maximum code security | 01/01/70 00:00 | |
| Worth it ? | 01/01/70 00:00 | |
| Protection with Patents | 01/01/70 00:00 | |
| the value... again... | 01/01/70 00:00 | |
| "OCR"ing a Design | 01/01/70 00:00 | |
| It's a brave man | 01/01/70 00:00 | |
| Specialist secure micros | 01/01/70 00:00 | |
| this is a different form of security | 01/01/70 00:00 | |
| Huge NREs? | 01/01/70 00:00 | |
| What if you don't bond out nPSEN? | 01/01/70 00:00 | |
| why not drop !EA | 01/01/70 00:00 | |
| Don't Drop !EA! | 01/01/70 00:00 | |
| Couldn\'t you do that in another way | 01/01/70 00:00 | |
| Eliminating /EA | 01/01/70 00:00 | |
| The value of PSEN | 01/01/70 00:00 | |
| not only... | 01/01/70 00:00 | |
| Brute-force copying | 01/01/70 00:00 | |
| well, maybe... | 01/01/70 00:00 | |
| Erase on tamper detect | 01/01/70 00:00 | |
| Make the chip hard to access | 01/01/70 00:00 | |
| It's quite impractical... | 01/01/70 00:00 | |
few thousand dollars ... Not at all | 01/01/70 00:00 |