From: Baltissen, R (Ruud) (ruud.baltissen_at_abp.nl)
Date: 2003-05-28 08:41:28
Hallo Greg, > Your "ReadIEEE" should change nRFD before it reads the data; it > should change nDAC after it reads the data. You are absolutely right. > 00 1 1 1 1 1 <- (I suspect that these are spurious > 01 1 1 1 1 1 signals. The computer is > changing its > 01 1 1 1 0 1 direction; but, it's fighting with > 00 0 0 0 0 1 the drive which still is talking!) > 48 0 0 0 0 1 > 48 0 0 0 1 1 <- (The signals are back to normal.) Thanks for all the comments. I understand the behaviour of both devices except this particular piece. What I did in the first place was looking for ATN = (L) after sending $04. Nothing found :( In fact an ATN = (L) is detected after '$01 $04 $01 $01'. FYI, I didn't change the original send routine, I only checked ATN between every transmission. But to make things even weirder: I decided to drop this problem for the moment and to remove all changes I made to trap ATN. But instead of typing 'load"$",8', I typed 'directory' out of habbit. Small suprise, data appeared on the sreen !!! You should know that when I tried to intercept the data sent by the 8032, nothing appeared at all. Unfortunately the data was scambled, that is, a number of random numbered BASIC-lines with garbage. Repeating 'directory' several times showed me a different output every time with one exception: the very first number was always the same. One more info: the line numbers were made of actual data. The only thing I can think of is placing $01 on the bus, pulling DAV (L) and see what happens. Hmmmm, these 'spurious signals' ie. all handshake lines (H), that is weird as well. Have a look yourself: during normal transmissions whatever happens, at least either NDAC or NRFD is (L) and in between both are (L). Except at this particular point. Could this mean someting ??? I already said, normally the sender waits for NDAC = (L) and NRFD = (H), source: 'PET revealed' and other docs. And yet someone, I suspect the drive, pulls DAV (L). Any comment is welcome. At least I have again some strings to clamp on :) -- ___ / __|__ / / |_/ Groetjes, Ruud \ \__|_\ \___| http://Ruud.C64.org =====DISCLAIMER================================================================= De informatie in dit e-mailbericht is vertrouwelijk en uitsluitend bestemd voor de geadresseerde. Wanneer u dit bericht per abuis ontvangt, verzoeken wij u contact op te nemen met de afzender per kerende e-mail. Verder verzoeken wij u in dat geval dit e-mailbericht te vernietigen en de inhoud ervan aan niemand openbaar te maken. Wij aanvaarden geen aansprakelijkheid voor onjuiste, onvolledige dan wel ontijdige overbrenging van de inhoud van een verzonden e-mailbericht, noch voor daarbij overgebrachte virussen. The information contained in this e-mail is confidential and may be privileged. It may be read, copied and used only by the intended recipient. If you have received it in error, please contact the sender immediately by return e-mail; please delete in this case the e-mail and do not disclose its contents to any person. We don't accept liability for any errors, omissions, delays of receipt or viruses in the contents of this message which arise as a result of e-mail transmission. Message was sent through the cbm-hackers mailing list
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