LeCroy LC564DL, Service Manual

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Theory of Operation 4-1
4. Theory of Operation
4.1 Processor Board : F9601-11-16
MPC603e
Processor
This processor board is based on the Power MPC603e processor.
It is a 64-bit RISC processor with 2x32kbyte cache. It features high speed
processing and fast memory accesses.
The F9601-11-16 processor is set to an internal clock of 96MHz and is used in a 32-
bit mode.
There are two “worlds” on the board:
•
the 32-bit world, including the main PowerPC processor, the dynamic RAM
modules and the VGA interface;
•
the 8 or 16-bit world, including all other on-board peripherals, external small
peripherals and acquisition board.
A MC68150 dynamic bus sizer is used as an interface between the two worlds.
Power Supplies
The board uses three power supplies from the main acquisition board: Vcc, +15V
and -15V. Vee is wired on a connector for board test purposes.
The +15V supply OP-amps on the 9601-11 board, and +15V and -15V supply small
peripherals.
The current processor needs a 3.3V power supply, all the rest of the logic needs
5V. All signals are TTL compatible.
The PLL circuit (88916) generates a PLL_LOCK signal, which is used to clamp
the 3.3V and 2.5V references as long as the 32MHz clock is not stable. The
processor also needs to be protected against too big voltage differences between
2.5V and 3.3V (diodes on the reference).
An OP-amp and a MOSFET transistor for each power supply are used. The
reference voltages are taken directly from the 5V power supply by a resistive
divider.
Capacitors and a few diodes ensure that the supplies do not exceed dangerous
levels at power-up, nor rise too fast.
32-bit Peripherals
There are only three devices hooked up on to the processors 32-bit data bus:
•
the VGA video controller
•
the DRAM system
•
the bus sizer, bridge to the 68k-like world