Analog And Other Output Signals; Circuit Description; Microcontroller And Peripheral Circuitry - Bayer HealthCare RapidPoint 400 Series Service Manual

Analog and Other Output Signals

Output Signal
POWER5V
VCC
PRN_7V
GND_PLANE
PWR_RET
PHASE 1..4
LED_DRIVE
VCC
GND_PLANE
BL1..2

Circuit Description

Microcontroller and Peripheral Circuitry

U21, a 80C552 microcontroller, controls the thermal printer and the touch
screen. This controller has a built-in, 10-bit ADC that measures diagnostic
signals as well as determines touch locations on the touch screen.
U12, a 64-macrocell PLD, expands the input/output (I/O) capability of the
microcontroller. This expanded I/O latches the data arriving at the parallel
port and provides output latching to control the printer motor and the touch
screen switches. It also includes latches for the lower address byte for
accesses to RAM and ROM.
80
Description
Power device for the 5 V power supply that powers the printer
motor. This signal conforms to the requirements outlined in
the Digital Inputs Signals section above.
Electronics 5 V power supply. This signal conforms to the
requirements outlined in the Digital Inputs Signals section
above.
Power supply signal for the print head. The voltage on this
line is between 4.2 and 7.0 V, with the ability to supply from
0 to 10 amps of current.
Ground reference signal for the electronics.
Ground reference signal for the power devices, such as
printer, backlight, and inverter.
Signals that drive the printer motor.
Anode of the diode in the paper sensing optocoupler. This
signal is pulled up to VCC through a 200 ohms resistor.
Electronics 5 V power supply. This signal conforms to the
requirements outlined in the Digital Inputs Signals section
above.
Ground reference signal for the electronics.
LCD backlight power supply voltage.
Rev. C