Re: [cc65] Uniform mass storage device discovery and file locations

From: Oliver Schmidt <>
Date: 2012-08-17 17:16:43

>>> just check with a simple LISTEN/SECLISTN/UNLISTEN or
>>> similar that a device is there

Okay, I#ve been trying to do my homework and came up with this:

lda <device>
jsr $ffb1 ; listen
lda #$00
sta $90   ; necessary ?
lda #$ff  ; or rather #$6f ?
jsr $ff93 ; lstnsa
ldy $90
jsr $ffae ; unlstn
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 ?

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Received on Fri Aug 17 17:17:41 2012

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