Specifications

Chapter 7: Theory of Operation
Motherboard Assembly
122
Motherboard Assembly
The motherboard assembly provides all system control and interface functions for the
oscilloscope. The motherboard contains a microprocessor, a hard disk drive interface,
ROM, RAM, keyboard and mouse interfaces, connections to the front panel assembly,
and serial and parallel interfaces.
Pressing the on/off button sends a signal to the motherboard. The motherboard then
signals the backplane assembly, which in turn sends a signal to tell the bulk 12V power
supply to turn on. When the power supply turns on, the remaining power supplies are
enabled and powered on. Then the main FPGA on the backplane assembly gets self-
configured from its PROM. Once it’s configured, the main FPGA asserts a signal to tell
the motherboard to power up and become fully functional. Figure 7- 2 illustrates this
system start- up process.
Figure 7-2 Power-Up Sequence
The hard disk drive is a high- capacity (> 250 GB), shock- resistant unit that stores the
oscilloscope operating system, the oscilloscope application, compliance application
information, calibration data, other data files, drivers for the boards and oscilloscope,
and user data files. The hard disk drive can also be used to store and recall oscilloscope
setups and waveforms.
It is common for the motherboard to be revised during the life of the oscilloscope, so
if a motherboard is replaced during a repair procedure, check to make sure it matches
the image on the hard drive. It is important for the hard disk drive image to match
the motherboard. If they do not match, the oscilloscope may not have the correct
Windows software drivers.
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