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View Full Version : Block size


Highlander
March 6th, 2004, 02:29 PM
What size block transfers will this puppy support?
GMPX
March 6th, 2004, 03:32 PM
What it takes :lol:
Highlander
March 9th, 2004, 02:32 PM
According to SAE you can only support up to 4k... with 4k blocks you can read a full pcm in 2 mins or so...

Although with the USB maybe the packet size can be "infinite" or ... a full FLOW of data from the PCM to the PC.
GMPX
March 9th, 2004, 02:52 PM
The problem with dumping the entire Flash in one hit (be it a 512K or 1024K PCM) is if there is any errors you would need to go back and re-read the entire thing, at least with smaller block sizes, be it, 512bytes, 1K, 4K or whatever else you want, you can do a checksum on each block read to make sure the rx'd data is valid and continue on, if there was an error, simply go back and re-read that block only.
The 'extra' time taken to do that isn't worth worrying about.

I don't believe the SAE defines anything GM does with their reflash process.

Remember too, most serial ports will run way faster than a PCM in 4x mode can spit out data.
Highlander
March 9th, 2004, 02:58 PM
Really interesting... but what are the chances of running into problems?
matbe do it in 12k chunks...

I thought that the serial port was at limitation... but I see it isn't...

Thanks for clarifying!