Vector Graphic 8-Inch Floppy Disk Controller
The Vector
Graphic 8" Floppy Disk Controller Board is a versatile single and
double density floppy disk controller implemented on a 5-by-10 inch
PCBA that plugs into the S-100 bus.
The
heart of the board is the 1793 Floppy Disk Formatter/Controller IC. The
1793 is a MOS LSI device that performs the function of a floppy disk
formatter/controller in a single chip implement.
The board is IBM 3740 compatible in single density mode (FM) and System 34 compatible in double density mode (MFM).
The
board contains all the necessary features to read/write and format a
double density diskette. These features include address mark detection,
FM and MFM encode and decode logic, window extension, and write
precompensation. In order to maintain compatibility, the board design
was made as close as possible with the computer interface, instruction
set and I/O registers being identical. Also, head load control is
identical.
The
processor interface consists of an 8-bit bi-directional bus for data
status, and control word transfers.The board also contains one serial
RS-232 1/0 port that is available to the user.
The
heart of the serial 1/0 port is the 8251 USART integrated circuit.
On-board circuitry allows the user to choose a serial transmission
speed between 110 baud and 9600 baud controlled by an on-board baud
rate generator. Provisions are also available for the speed to be
controlled by an external clock. Jumper areas have been provided to
allow the user to choose whether the serial port will be configured as
DCE or DTE. 
8-INCH Floppy Disk ControllerBlue Board 
8-INCH Floppy Disk ControllerGreen Board
Related Links
Dual Stor
System 2800