| ??? 02/21/07 14:25 Read: times |
#133426 - ah so... Responding to: ???'s previous message |
So, if I understand it correctly, even if /EA is latched, the bootrom follows the _current_ state of /EA in the AT89C' and P89C'?
As you can see, the SST/P89V' has a rather intricate lock bits system, but it appears to me at the first glance that it would be impossible to use a system such as you mentioned with the "/EA goes low ~500 ms after reset", with P89V'... From those 3 lockbits only 1 bit remained in the Philips documentation of P89V'; but, as one of the proofs that they simply copied the SST documentation and erased parts of it they did not want to be there, there is a mention of "Level 4 security" in the /EA pin description... Jan Waclawek |
| Topic | Author | Date |
| 89v51 IAP using ext code PROM | 01/01/70 00:00 | |
| No | 01/01/70 00:00 | |
| how do you do that? | 01/01/70 00:00 | |
| It runs on AT89C51 and P89C51 | 01/01/70 00:00 | |
| Internal IAP with external code | 01/01/70 00:00 | |
ah so... | 01/01/70 00:00 |