ACCELERATED COMPUTER TECHNOLOGY, INC. UNIVERSAL FLOPPY DISK CONTROLLER Card Type Floppy drive controller Chip Set Unidentified Maximum Onboard Memory None I/O Options Floppy drive interface (3) Data Bus 8-bit ISA Floppy drives supported Four 360KB or 720KB drives Four 360KB, 720KB, 1.2MB, or 1.44MB drives [Image] CONNECTIONS Function Label Function Label 34-pin floppy drive J1 34-pin floppy drive J3 interface interface 37-pin floppy drive J2 interface Note: J1 is the connector for drives A: and B:, either J2 or J3 can be used to connect drives C: and D:. USER CONFIGURABLE SETTINGS Function Label Position Step rate of floppy drive A is 3 Ms SW1/1 On Step rate of floppy drive A is 6 Ms SW1/1 Off Step rate of floppy drive B is 3 Ms SW1/5 On Step rate of floppy drive B is 6 Ms SW1/5 Off Step rate of floppy drive C is 3 Ms SW2/1 On Step rate of floppy drive C is 6 Ms SW2/1 Off Step rate of floppy drive D is 3 Ms SW2/5 On Step rate of floppy drive D is 6 Ms SW2/5 Off Drive order will be MODE 1(see SW3/1 Off MISCELLANEOUS TECHNICAL NOTE 2) Drive order will be MODE 2 (see SW3/1 On MISCELLANEOUS TECHNICAL NOTE 2) UFDC is the primary floppy drive SW3/2 Off controller UFDC is the secondary floppy drive SW3/2 On controller » EPROM enabled SW3/3 On EPROM disabled SW3/3 Off » TYPE 1 or 2 drives (see MISCELLANEOUS W1 Pins 1 & 2 TECHNICAL NOTE 1) closed TYPE 2 or 3 drives (see MISCELLANEOUS W1 Pins 2 & 3 TECHNICAL NOTE 1) closed » Pin 2 on the interface cable is an W2 Pins 1 & 2 output signal closed Pin 2 on the interface cable is an W2 Pins 2 & 3 input signal (TYPE 2 drives only) closed FLOPPY DRIVE A CONFIGURATION Type SW1/2 SW1/3 SW1/4 360KB (5.25) On On Off 1.2MB (5.25) On Off On 720KB (3.5) On Off Off 1.44MB (3.5) Off On On None On On On FLOPPY DRIVE B CONFIGURATION Type SW1/6 SW1/7 SW1/8 360KB (5.25) On On Off 1.2MB (5.25) On Off On 720KB (3.5) On Off Off 1.44MB (3.5) Off On On None On On On FLOPPY DRIVE C CONFIGURATION Type SW2/2 SW2/3 SW2/4 360KB (5.25) On On Off 1.2MB (5.25) On Off On 720KB (3.5) On Off Off 1.44MB (3.5) Off On On None On On On FLOPPY DRIVE D CONFIGURATION Type SW1/6 SW1/7 SW1/8 360KB (5.25) On On Off 1.2MB (5.25) On Off On 720KB (3.5) On Off Off 1.44MB (3.5) Off On On None On On On EPROM ADDRESS CONFIGURATION Address SW3/4 SW3/5 SW3/6 SW3/7 SW3/8 C8000h On On Off On On » CA000h On On Off On Off CC000h On On Off Off On CE000h On On Off Off Off D0000h On Off On On On D2000h On Off On On Off D4000h On Off On Off On D6000h On Off On Off Off EPROM ADDRESS CONFIGURATION (CON’T) Address SW3/4 SW3/5 SW3/6 SW3/7 SW3/8 D8000h On Off Off On On DA000h On Off Off On Off DC000h On Off Off Off On DE000h On Off Off Off Off E0000h Off Off On On On E2000h Off Off On On Off E4000h Off Off On Off On E6000h Off Off On Off Off E8000h Off Off Off On On EA000h Off Off Off On Off EC000h Off Off Off Off On EE000h Off Off Off Off Off MISCELLANEOUS TECHNICAL NOTE NOTE 1: Due to the tight tolerances in the construction of a 3.5" floppy disk, the write current applied to the heads of the drive needs to be adjusted for either 720KB disks or 1.44MB disks. Floppy disk drive manufactures have used three different mechanisms to modify the write current. They are: TYPE 1:These drives read the current on pin 2 of the interface cable, a 1.44MB disk is assumed for a high current, and a 720KB disk is assumed for a low current. TYPE 2: These drives have a sensor that looks for a cutout in the plastic shell of the disk. If the cutout is present, a 1.44MB disk is assumed. TYPE 3: These drives are found on the IBM PS/2 line of products. They read the current on pin 2 of the interface cable in the opposite manner of TYPE 1’s. That is, a high current signifies a 720KB disk and a low current a 1.44MB disk. NOTE 2: If you have installed more than 2 floppy drives in a system, you have a choice on how the controller treats the third and fourth drives. MODE 1 sets the drives to A:, B:, C:, & D:, in this system your hard drive will be the first available letter. If you have 3 drives installed it will be D:, and if you have all four installed it will be E:. MODE 2 sets your first two floppy drives to A: & B:, and assigns C: to the hard drive. To install additional floppy drives under this system you will need to load a device drive at boot time.