Purpose: Set up a logical file
Call address: $FFBA (hex) 65466 (decimal)
Communication registers: A, X, Y
Preparatory routines: None
Error returns: None
Stack requirements: 2
Registers affected: None
Description: This routine sets the logical file number, device address, and secondary address (command number) for other KERNAL routines.
The logical file number is used by the system as a key to the file table created by the OPEN file routine. Device addresses can range from 0 to 31. The following codes are used by the Commodore 64 to stand for the CBM devices listed below:
|4||Serial bus printer|
|8||CBM serial bus disk drive|
Device numbers 4 or greater automatically refer to devices on the serial bus.
A command to the device is sent as a secondary address on the serial bus after the device number is sent during the serial attention handshaking sequence. If no secondary address is to be sent, the Y index register should be set to 255.
How to Use:
FOR LOGICAL FILE 32, DEVICE #4, AND NO COMMAND: LDA #32 LDX #4 LDY #255 JSR SETLFS