On Fri, 20 Oct 100 g.j.p.a.a.baltissen@kader.hobby.nl wrote: > > > > There is an end of transmission signal sent from the drive, apart from the > > IEEE protocol, that indicates that loading has terminated. I am not > > familiar with what that actually is.... > > That is the EOI-signal which is a sepperate line on the IEEE-bus. The > EOI-signal on the IEC-bus is created by fiddling around with some timings. > > The bytes where I am talking about are $48 and $60 which appear after the drive > has sent two or three bytes. Why is the computer sending these bytes? Why do > they appear in the middle of the transmission of the third byte? A little bit > further you se the C= transmits a $5F, Untalk, as well. Why didn't it earlier? I don't know why the drive is sending extra bytes, but it clearly does and this is allowed for in the load routine. These bytes are ignored and the computer waits for an EOI. While it is waiting, the status byte must be kept valid, i.e. set as valid data received and not timed out. Part of the wait loop is to set the status read error off each time through the loop. I see also that the "Tool Kit" book says the computer sends the untalk as a substitute for an EOI from the computer. On the IEEE drives, you may have to send an actual EOI from the computer. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tml.hut.fi.
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