| ??? 10/03/05 06:25 Read: times |
#101837 - no meaning Responding to: ???'s previous message |
Sebastian Stehrn said:
How can i to know from internal programm, that external EEPROM chip installed or not ?
The derivative you use has 64kb of internal program memory (memory range 0x0000...0xFFFF) and no feature to set its size smaller. So there is no software way to check for external program memory presence: any MOVC or JMP will route fetch for internal flash memory. Moreover there is no sense to do it because you cannot utilize external program memory without hardware changes anyway. If you wish to utilize that EEPROM then unconnect of its /OE pin (or /CE one - see the schematic of MB for details) from /PSEN pin and tie it to /RD pin of MCU. Then use this as external data memory (via MOVX). Regards, Oleg |
| Topic | Author | Date |
| AT89C51ED2 and external EEPROM | 01/01/70 00:00 | |
| If serial, try a write and a read, if pa | 01/01/70 00:00 | |
| some comments | 01/01/70 00:00 | |
| why "of course" most is serial | 01/01/70 00:00 | |
| I don't need 128K programm memory | 01/01/70 00:00 | |
| if it is not used, you can not detect it | 01/01/70 00:00 | |
| I must to do it by software | 01/01/70 00:00 | |
| You should have thought of that before y | 01/01/70 00:00 | |
| Re: hardware required | 01/01/70 00:00 | |
| leave harvard structure! | 01/01/70 00:00 | |
| it depends | 01/01/70 00:00 | |
| no meaning | 01/01/70 00:00 | |
| Software solution | 01/01/70 00:00 | |
| Sure, but why? | 01/01/70 00:00 | |
| Ask Sebastian | 01/01/70 00:00 | |
| Please explain further | 01/01/70 00:00 | |
| some explayning | 01/01/70 00:00 | |
| Use other device | 01/01/70 00:00 | |
XDATA? | 01/01/70 00:00 |