From: David Wood (jbevren_at_starbase.globalpc.net)
Date: 2004-09-09 15:08:47
0 means 256 bytes, I remember reading this somewhere. It probably has something to do with the way the countdown loop is run: dex:bne would cause 0 to be 256 bytes, 1 to be 1, 255 to be 255. -David On Thu, 9 Sep 2004, Marko [iso-8859-1] Mäkelä wrote: > Hi Ruud, > > > > Hmm, if you were copying individual files, wouldn't it be > > > possible to tell the CBM-HD to LISTEN and the 8250 to TALK? > > > > You mean sending a TALK to the 8250 and a LISTEN to CBM-HD? On itself a good > > idea as there is only one transfer par byte instead of two as it is now. > > Transferring files isn't a problem as the sender will activate EOI at the > > end of the file. But how are you going to tell the sender to activate EOI at > > the 256th byte? > > I didn't think that it would be a solution for disk transfers; I just mentioned > it as a compatibility test case for your CBM-HD. > > Come to think of it, it might work also for disk image transfers. You'd write > a program for the 8050 or 8250 and start it with M-E. The program would wait > for the LISTEN or TALK request, and then it would start transfering disk > sector data. The CBM-HD would receive all data in a single file. Copying > back to disk wouldn't work as easily. > > > But the docs state that one can only read from 1 up to 255 bytes. I need to > > read 256. I could try if 0 is translated as 256 otherwise I have to do it in > > two batches. > > cbmlink uses M-R length 0 and copies 256 bytes at a time. I don't remember > if 0 means "infinite"; you will have to test it. > > > More worrying is the fact that I only can write up to 34 byte. Is the > > computer to blame or the drive? > > The drive. It has a fixed-size command buffer. It'll input the data to the > buffer, and then copy it to the desired location. M-R reads directly from > the specified address. > > What language is CBM-HD written in? Are you planning to release the source > code? I'd be interested in a GNU/Linux port. I have an old IEEE-488 ISA card > lying around. I hope that the code is modular enough to support different > types of IEEE-488 interfaces. > > Marko > > Message was sent through the cbm-hackers mailing list > Message was sent through the cbm-hackers mailing list
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