| ??? 12/20/07 04:01 Read: times |
#148532 - Re: I see no mention of !EA Responding to: ???'s previous message |
For execution in external code memory, EA tie to 0V before and after power on (reset) with voltage monitor MAX810.
According to ATMEL data sheet, even HSB (Hardware security byte) shows security level is 4, it is still not reasonably because it write "external execution is disabled if code roll over beyond 7FFFh". CSEG AT 0 LJMP PowerON CSEG AT 0100h PowerON: Loop_0: MOV R6,#0 Loop_1: MOV R7,#0 Loop_2: DJNZ R7,Loop_2 DJNZ R6,Loop_1 CPL SIG_LED JMP Loop_0 Above code size large enough to roll over? It work in FM0 but not in external ROM. |
| Topic | Author | Date |
| T89C51CC01UA not run on external code mem | 01/01/70 00:00 | |
| T89C51CC01UA not run on external code memory (2) | 01/01/70 00:00 | |
| I see no mention of !EA | 01/01/70 00:00 | |
| Re: I see no mention of !EA | 01/01/70 00:00 | |
| clock and ALE | 01/01/70 00:00 | |
| Re: clock and ALE | 01/01/70 00:00 | |
| Re: clock and ALE | 01/01/70 00:00 | |
| hardware security byte | 01/01/70 00:00 | |
| not an admonsihment, just a thought | 01/01/70 00:00 | |
Re: hardware security byte | 01/01/70 00:00 | |
| T89C51CC01UA not run on external code mem | 01/01/70 00:00 |