Valleylab Force FX-C - Control Board; Microcontrollers; Main Microcontroller

Control Board
Control Board
'When resistance between the Patient Return Electrode receptacle pins
exceeds 20 ohms, the REM Alarm indicator flashes red, a tone sounds
twice, and RP output is disabled. The indicator remains illuminated red
until you correct the condition causing the alarm. Then, the red indicator
light is extinguished and RF output is enabled.
For additional information, refer to RDvI Circuit later in this section.
Refer to Section 9 for Components and the Schematics Supplement for
Board Drawings and Schematics.
The Control board contains the circuitry that controls the generator,
including the indicators and switches on the Display board and the RP
output stage on the PO\ver Supply IRF board. Firmware on the control
board performs many diagnostic and initialization routines. Errors are
reported as alarm numbers on the front paneL
The Control bomd interfaces with the Power Supply IRF board through a
96-pin card edge connector. It interfaces with the Display board through a
64-pin ribbon cable.
Microcontrollers
Two microcontrollcrs on the Control board control the Force FX-C
generator. These microprocessors commtmicate with each other through a
shared RAM. One, the main microcontroller (U5) performs all system
functions, except the time-critical real time feedback control of generator
RF output. This is handled by the feedback microcontroUer (Ull), vvhich is
a separate, dedicated micro controller. All system analog signals are
available to these microcontrollers.
A third microcontroller (U9) functions as an application-specific
integrated circuit, or ASIC. It generates the RF drive waveforms (T_ON\)
for the RF output
Main Microcontroller
The main microcontroller (U5) is an 8OC562 that incorporates an 8-input
multiplexed 8-bit AID converter. The main microcontroller is responsible
for overall system control. It monitors all dosage error functions and
safety circuits. It implements the user interface, including activation
control. It is primmily responsible for the following 10 functions:
• Segment display drivers and LED update
• Power control buttons, mode buttons, and the activation interface
• Serial port interface
• Alarm handling
• REM
Force FXTM-C Service Manual 4-5