Analogue-sequencer

-thanks ...COLIN,the famous cheksum..i've melt in the jd 990 roland
..for edit a template with an external surface control(novation sl
25)..i 've broken my head with...;-)it's more easy to drink a bad 
french wine(i'm french)...Best regards ..

-- In analogue-sequencer@yahoogroups.com, "Colin Fraser" <colin@...>
wrote:
>
>  
> > when you talk about
> > "surprise"do you think the chip is damaged?
> 
> No, by a "surprise", I mean you may get unexpected behaviour in the
OS, such
> as a crash or other weirdness.
> 
> The most likely way to get a checksum error on the P3 would be to do an
> incomplete firmware update.
> The firmware is loaded in blocks of 128 bytes. Each block is written
to the
> flash memory in the CPU as it is received as a sysex block.
> At the end of the sysex file is a checksum.
> The checksum is stored in the boot block, and compared with a checksum
> calculated from the flash on every boot.
> If the boot block checksum doesn't match the generated checksum, the
boot
> loader shows the error message.
> 
> If you were to do half an OS update and then stop, some of the flash
would
> be over-written, but not all, so the checksum would be wrong.
> This would be an unsafe OS, as it would be the first part of one
build on
> top of the latter part of another.
> 
> If you get a checksum error without having recently updated the
firmware,
> then it is most likely just a spurious error that has occured in a
single
> byte of flash. Continued booting of the OS may work with no problem,
but a
> re-flash via sysex would be strongly recommended.
> 
> Best regards,
> Colin Fraser
> Sequentix Music Systems Ltd
> http://www.sequentix.com
>