| ??? 06/13/07 20:44 Read: times |
#140714 - I am still not convinced... Responding to: ???'s previous message |
Bryan,
how did you verify you did not set the /2 flag? Using an oscilloscope? Bryan Randall said:
We are running our V51RD2 with a 32Kx8 NVRAM chip. We have attempted to set the EXTRAM bit to ensure the MCU can access the external memory. As per behaviour of EXTRAM bit, the datasheet provides extensive information. As I said above, if the internal-external RAM is enabled, (EXTRAM=0, which is the default) MOVX @Ri cease to access the true-external RAM altogether; and MOVX @DPTR accesses only that part of true-external RAM which is above the 768 bytes (yes, it is NOT 1kB, the advertisement slightly lies as usually). You hint that you are using C, can you please be more specific? Whether MOVX @Ri is used or not, that is compiler specific. Can you give us at least the memory map of your device? --- Anyway, nothing of what has been said above justifies the "stopped working with external code memory when programmed". I see only the /2 flag and the security flags as potentially suspicious. JW |
| Topic | Author | Date |
| 89V51 Code running from FLASH vs EPROM | 01/01/70 00:00 | |
| faulty code | 01/01/70 00:00 | |
| timing? | 01/01/70 00:00 | |
| I need some shematics and programe code using asm | 01/01/70 00:00 | |
| 89V51 Code running from FLASH vs EPROM | 01/01/70 00:00 | |
| hummm.... | 01/01/70 00:00 | |
| OK, We're on to something.... | 01/01/70 00:00 | |
| questions | 01/01/70 00:00 | |
| OK, then don't switch on the /2 flag! | 01/01/70 00:00 | |
| /2 Flag | 01/01/70 00:00 | |
| and the code security flag? | 01/01/70 00:00 | |
| PLM51 Question. | 01/01/70 00:00 | |
| TWO WRONGS | 01/01/70 00:00 | |
| I am still not convinced... | 01/01/70 00:00 | |
| Still a Problem, but........ | 01/01/70 00:00 | |
| P89v51 does have some differences | 01/01/70 00:00 | |
had to wait 5 minutes on someone | 01/01/70 00:00 |