Talk:Commodore 1540

Origin of the name?
How did the C-1540 come up with its name? The last two digits make it sound suspiciously similar to the 4040. What does the number '15' represent? 216.99.201.230 (talk) 06:18, 6 June 2009 (UTC)


 * The number "15" relates to the TALK/LISTEN protocol inherent in communicating with it.  To pass commands over to the disk drive, it was necessary to pass a command through channel 15 so it could be acted on by the drive alone, without further supervision from the "host" computer.

For instance, the following BASIC program lets you format a diskette that has been inserted into the disk drive:


 * 100 OPEN 15,8,15
 * 110 PRINT#15,"N0:FORMATTING COMMAND,AB"
 * 120 IF ST<64 THEN 120
 * 130 IF ST>64 THEN GOTO 200
 * 140 CLOSE 15
 * 150 END
 * 160
 * 200 REM (put error handler here)

If you are familiar with the TALK/LISTEN protocol, a similar sequence is involved in assembly language, e.g.,


 * LDA #$08        ; device 8
 * JSR   TALK
 * BIT    $90         ; examine status flags stored in page zero
 * BMI  ERROR_HANDLER
 * LDA  #$0f       ; secondary address 15
 * JSR   TKSA
 * BIT   $90
 * BMI ERROR_Handler

and so on. Pretty much ordinary, nothing too special once you get the hang of it.

All of the disk drives in the 15xx series use channel 15 for the channel you pass commands to it.

However, most people note a similarity with the Commodore 4040, which has a more extensive BASIC command set for managing ordinary disk operations. Dexter Nextnumber (talk) 02:37, 12 November 2009 (UTC)