Hi, Just for the records - here's again the code snipet and my questions - which the answer below refers to... lda <device> jsr $ffb1 ; listen lda #$00 sta $90 ; necessary ? lda #$ff ; or rather #$6f ? jsr $ff93 ; lstnsa ldy $90 jsr $ffae ; unlstn tya bpl <present> <not present> However I have several questions: - Is it really necessary to initialize $90 - What is the right high nibble for "opening" the cmd channel here $F or $6 ? - Is it correct to assume that unlstn doesn't trash Y ? - Is it correct that $90 must be saved before calling unlstn ? > P. S. Unless someone replies earlier, I would need a few days (travelling now) to check my stuff at home to answer the questions about status ($90) byte. My bet is that answer to both is "yes" but have to double check the reasons, which I sort of only recall now - so don't take them as true and correct. [*] > > * - 1) to start afresh, 2) to allow particular bits to be affected without losing previous information from the other ones As noone else has answered yet I'd for sure appreciate if you would take the time after your return to re-check ! The code linked to a few posting back (http://codebase64.org/doku.php?id=base:detect_drives_on_iec_bus) sets the status to zero before calling LISTEN while mine above does it after that call. I'm not sure if this is of significance. Could LISTEN already fail (and set the status ?). Would LSTNSA probably even reset the status back to zero? ...? It would be great to know the really correct sequence here! Regards, Oliver ---------------------------------------------------------------------- To unsubscribe from the list send mail to majordomo@musoftware.de with the string "unsubscribe cc65" in the body(!) of the mail.Received on Mon Aug 20 14:08:53 2012
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