Detector Main Board (Vwm) - Agilent Technologies 1100 Series Reference Manual

Detector Main Board (VWM)

This board controls all information and activities of all assemblies within the detector
module. The operator enters parameters, changes modes and controls the module,
through interfaces (CAN, GPIB or RS-232C), connected to the user interfaces
ASIC — Application Specific Integrated Circuit
The 304-pin application-specific integrated circuit (ASIC) provides interfacing to
external devices through drivers, including GPIB, CAN, APG remote, and RS-232C. It
is directly connected to the four control LEDs located near the connectors on this board
and the 8-bit configuration switch which is used to configure the address for the GPIB
communication, Baud rate for RS-232C transfer and so on. For switch settings,
53
In addition, it controls the cooling fan through the PWM (pulse width modulation)
driver. Movement of the cooling fan is sensed by the hardware and the microprocessor.
Mainprocessor
The Motorola MC 68332 microprocessor acts as mainprocessor with a clock frequency
of 16 MHz and exchanges data with the ASIC through the core bus as well as with the
PSRAM (pseudo-static random access memory) of 2 × 512 KB, flash EEPROM
(electrically erasable programmable read only memory) of 1 MB and 1 × 32 KB
battery-backed NV-RAM (non-valuable).
Battery life is laid out to last for more than 25 years under normal operating conditions.
FPGA (Field Programmable Gate Array)
Almost all control and communication of the ADC boards (VWA) and digital section of
grating motor driver is programmed in FPGA.
Firmware
For an outline of the firmware, see
Leak Converter
This block consists of a PTC (resistor with positive temperature coefficient) for the leak
identification and a NTC (resistor with negative temperature coefficient) for the
ambient temperature measurement. This assures that temperature changes are not
identified as a leak. A leak would cool down the PTC and its change in resistance
1100 Series Variable Wavelength Detector Reference Manual 185
on page 209.
Introduction to the Variable Wavelength Dector
"Firmware Description"
Table
on page 197.
6