| ??? 10/03/05 09:31 Read: times |
#101841 - Software solution Responding to: ???'s previous message |
You can connect the EEPROM as data memory (/RD to /OE).
And then you implement a custom bootloader which do some checking, if there is a valid program inside the EEPROM (e.g. CRC check, magic numbers) and if it differs from the internal Flash. And then the bootloader copy the content of the EEPROM into the internal Flash and jump to 0x0000. The reset vector must be moved to the custom bootloader and the custom bootloader should be excluded from overwriting by the external EEPROM. But for such an approach I would suggest a serial EEPROM (24C512) to lose only 2 instead 17 IO-pins. Peter |
| 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 |