Control Board
5-6
Force EZ-C Series Service Manual
Main Microcontroller Memory
An ST microelectronics PSD835G2 programmable systems device (U3) provides
program memory (512K x 8 external flash memory) and data memory (2K x 8
external battery-backed static RAM) for the main microcontroller. Additional
data memory is available from these sources:
•
256 x 8 microcontroller internal RAM
•
4K x 8 external static RAM (U4) shared with the feedback microcontroller
•
128 x 8 external battery-backed static RAM inside the real-time clock (U1)
Battery-Backed RAM
A socket on the Control board contains a 3.0 V lithium button cell battery (BT1)
that provides backup power for the 2K x 8 external RAM on the PSD835G2
device (U3) and the 128 x 8 external RAM on the real-time clock (U1) used by
the main microcontroller. The battery-backed RAM stores statistical data about
generator use, calibration constants, special features settings, and last setup
parameters.
Feedback Microcontroller
The feedback microcontroller (U11) is an 80C562. It receives commands from the
main microcontroller and, when the generator is activated, establishes the
appropriate relay closures and activates RF output. The feedback microcontroller
continually adjusts the output signal of the generator by controlling the high
voltage DC power supply and the RF clock circuitry. The feedback
microcontroller serves the following primary functions:
•
scaling relay control and output relay control
•
T_ON ASIC waveform control
•
leakage control (coag)
•
constant voltage, current, and power feedback control
•
ECON initialization
•
real-time information update (actual voltage, current, power, impedance,
Instant Response System)
•
memory tests
Feedback Microcontroller Memory
An ST microelectronics PSD835G2 programmable systems device (U6) provides
program memory (512K x 8 external flash memory) and data memory (2K x 8
external static RAM) for the feedback microcontroller. Additional data memory is
available from these sources:
•
256 x 8 microcontroller internal RAM
•
4K x 8 external static RAM (U4) shared with the main microcontroller
