Theory of Operation
The HP 16500B Logic Analysis System
System Overview Theory
HP 16500B
The HP 16500B is the mainframe for the Logic Analysis System.
Microprocessor Board The microprocessor board contains all the interface circuitry for managing data flow between the mainframe components and the optional boards. The microprocessor used is a Motorola 68EC030.
Mother Board Located on the mother board are the intermodule bus and the fan speed control circuit. The mother board consists of seven card slots: five are used for the optional acquisition and stimulus boards, one for the microprocessor board, and one for the power supply. The only active components on the mother board are for the fan speed control circuit. The heat-sensing thermistor for the fan speed control circuit is located on the microprocessor board.
Flexible Drive The flexible disk drive uses 3.5-inch, double-sided, double-density disks. All of the disk drive control circuitry is located on the microprocessor board.
Hard Disk Drive The hard disk drive, located beneath the rear fans, is an 85 Mbyte DOS-formatted high-reliability drive. The disk drive circuitry is located on the microprocessor board and on the hard disk drive assembly.
Color Module The color module display is an eight-plane color system. Each plane has a resolution of 576 pixels by 368 lines. The display is non-interlacing and is refreshed every 1/60 of a second (not synchronized to the ac line). The horizontal and vertical sync signals are generated by the CRT controller located on the microprocessor board. Color information for the display is generated on the microprocessor board. The display RAM and the color palette are also located on the microprocessor board.
Front-Panel Board The front-panel board is based on the Hewlett-Packard Human Interface Link (HP-HIL) and consists of the touchscreen system, the front-panel control knob, the optional mouse, and the optional keyboard. All of the touchscreen and knob circuitry of the HP-HIL is located on the front-panel board and the controller for the link is located on the microprocessor board.
Power Supply The power supply provides the following regulated voltages:
-12.0 Vdc | +5.0 Vdc | +3.5 Vdc |
+12.0 Vdc | -5.2 Vdc | -3.25 Vdc |
+120 Vdc | | |
The +120.0 V supply is used only by the color module. Current limiting, overvoltage protection, and thermal shutdown are provided for all supplies.
