| ??? 05/12/08 06:57 Read: times |
#154697 - hummmm.... Responding to: ???'s previous message |
Charles Townsend said:
if you can program it with your universal programmer then the chip should be fine. Well, not quite. Parallel programmability is often achieved by relatively straighforward access to the internal FLASH, and often the processor is not involved at all, ergo, it is programmable and readable even if the processor core is fried, or some of the I/O pins. I don't know how it is for the P89C51RD2whatever, but I would not count on it. Charles Townsend said:
In the Atmel version (AT89C51RD2) when I had trouble with the bootloader I would just read a brand new chip with the universal programmer and copy it to the one that was not working including the fuse settings. (I use a labtool 48XP universal programmer). Works every time for restoring ISP functionality. If you erase the chip with your universal programmer, you will erase the bootloader!
Atmel claims that in the AT89C51xD2 the bootloader is in ROM (not reprogrammable nor erasable). It might very well be that in fact it IS Flash, just Atmel does not give away the method to erase and (re)program it. However, corrupting just the flash flags (XAF) might result in the same symptoms as if the bootloader itself would be corrupted - and, reprogramming the flags would certainly help, too. This was different in the Temic version (T89C51RD2), which was also sold for some time with the Atmel logo, but without the AT prefix. Here, the bootloader was indeed in FLASH and could be easily rewritten (or, if you want, corrupted). Charles, can you please confirm which one did you use, and what exactly were your findings? Charles Townsend said:
I have the file here somewhere, not sure if it will be the same for the device you are using. Certainly not. The Philips chip is completely different as far as IAP (which is the "heart" of the bootloader) is concerned. JW |
| Topic | Author | Date |
| 89c51rd2 boot loader | 01/01/70 00:00 | |
| WHICH RD2? | 01/01/70 00:00 | |
| actually there are 3 | 01/01/70 00:00 | |
| ok, then 4 | 01/01/70 00:00 | |
| And shortly there will be 5 | 01/01/70 00:00 | |
| Funny | 01/01/70 00:00 | |
| it's supposed to be UART ICP | 01/01/70 00:00 | |
| what's the timestamp? | 01/01/70 00:00 | |
| Ooops | 01/01/70 00:00 | |
| ISP Circuit ? | 01/01/70 00:00 | |
| to furno | 01/01/70 00:00 | |
| try this | 01/01/70 00:00 | |
| hummmm.... | 01/01/70 00:00 | |
| both atmel and Temic | 01/01/70 00:00 | |
| Just to make sure | 01/01/70 00:00 | |
| sorry guys,nw its precise | 01/01/70 00:00 | |
| that\'s it | 01/01/70 00:00 | |
@Eric | 01/01/70 00:00 |