Fukuda CardiMax 2, Service Manual

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2-5
Chapter 2 Operational Description Operational Description

Sensor Drive Unit
The block diagram of the sensor drive unit is shown below.
The paper end sensor and mark sensor are controlled as follows.
The sensor drive pulse is output from the FPGA and input to the phototransistor via buffer.
The sensor output signal with the voltage corresponding to the reflection degree, is amplified by the amplifier and
compared with the threshold value.The compared detected signal is inputted to the FPGA, and after the chattering
process in the FPGA, paper end and mark status are fixed.These information are used for motor and thermal signal,
and transferred to the CPU as detected result.

USB I/F Unit
The block diagram of the USB I/F unit is shown below.
The USB I/F unit has a full speed compliant circuit for three ports.A data communication with the CPU is performed
via dedicated transceiver.Communication with each port is performed by USB hub device.
A USB power control device is mounted to protect against overcurrent.When overcurrent is detected, the power
supply to the USB device is ceased, and transfers the overcurrent status signal to the CPU.

Sound I/F Unit
The block diagram of the sound I/F unit is shown below.
The sound source data from the CPU and FPGA is transmitted to the piezoelectric buzzer as PWM signal.
㻲㻼㻳㻭㻌
㻮㼡㼒㼒㻚㻌
䝨䞊䝟㻌
Paper
Sensor
Output
Detection
Signal
Threshold
Sensor Drive
Pulse
Amplify Compare
Photo
Transistor
Paper
㻌
㻌
㻌
㻯㻼㼁㻌
㻌
㻌
㼁㻿㻮㻌㻴㼁㻮㻌
㼁㻿㻮㻌
Port 1
㻌
㻌
㼁㻿㻮㻌
Port 2 㻌
㼁㻿㻮㻌
Port 3
㻌
USB
Transceiver
USB Power
Control Device
㻌
㻯㻼㼁㻌
㻼㼃㻹㻌
㻌
Piezoelectric Buzzer