Labels:text | black and white | document | parallel OCR: 4040 Dual Disk Controller RAM Usage The 6530 Disk Controller contains 64 bytes of RAM for use by the 5504 CPU: 0000-001F is used for storage 53 0020-003F is the stack seen by the 6504 al 0100-013F Los Label Description 0020 -003F 0040 VIAA stack for 6504 MOS 6522 $0010-004F bits 1-2 frequency (bit density) 0000 CLOCK 0001 -0002 MTRTM controllers clock 0040 VB port b bit 3 write protect 1 - yes motor timer : drive 0 / drive 1 bit 6 sync detect 1 = no, 0 = yes (+) when motor fully on bits 0-1 stepper motur drive *1 bits 2-3 stepper motor drive "0 0083 DDRB appears as unused by FDC 0003 -0004 (0) when motor should be turned off 0084 -008E data direction register b DRVST drive status words bits 0-5 track " bit 4 motor I off bit 5 motor Dofl OUBF MITAT Timer/1024 bit 6 stepping 0= no. 1 = yes b ...
