METRON QA-ES, Руководство пользователя и обслуживания, Страница: 30 / 55

(See QA-ES Processor Board Schematic Diagram 1) . The mi-
croprocessor system is in PCMCIA card format (U1). It com-
prises a MC68HC16 microprocessor with I/O, 256K Flash ROM
and 64K RAM. It can be reprogrammed or replaced when up-
grading the software. The processor's I/O includes an asynchro-
nous serial port (ACIA), synchronize serial port, parallel I/O,
A/D converter and PWM output. In addition, 8 bit of the data
bus are accessible, as well as chip-select lines for direct access
to the external I/O.
The processor is timed with a 16.67 MHz timer frequency, con-
trolled by an internal crystal in the component. To check the
timer frequency, a 1024 Hz square signal is applied to one of
the PWM outputs. The signal can be measured at pin TP 1.
Ul3 is an EEPROM connected to the processor component via a
parallel I/O. Ul3 saves the calibration parameters for the Sam-
pling Unit. The parameters can be stored independently of the
processor component so that the QA-ES does not have to be re-
calibrated when upgrading the software.
3. Function Keys
(See QA-ES Processor Board Schematic Diagram 1) . The QA-
ES is operated by touch keys and a universal digital encoder.
The encoder, or 'knob', will be given different functions de-
pending upon the parameters that are to be changed. The en-
coder is connected to two touch keys with unchangeable func-
tions, 'ENTER' and 'CANCEL'. The QA-ES is operated from 5
'soft-keys' linked to menus shown on the display.
Latch U2 buffers data from touch keys SW1-SW7. If you press
one of the keys, power will flow into the base at Q1 via RP1,
thus controlling an interrupter input on the processor unit. When
the interrupter input is activated the processor reads latch U2
latch to find out which key was pressed. The same interrupter
input is activated via diodes D1 and D2 when operating the en-
coder. The encoder is read via I/O ports on the processor com-
ponent.
4. Display
(See QA-ES Processor Board Schematic Diagram 1). The QA-
ES is equipped with a 240 x 64 dot graphic display with a built-
in character generator. When in character mode, the display
shows 40 x 8 characters. The display is controlled by the pro-
cessor unit via the data bus. The display's contrasting voltage is
regulated with voltage regulator U12. Voltage (and contrast) are
controlled with the potentiometer R15. This is the only point of
adjustment at the processor board.
The display offers EL background light to make it easier for the
user to read. U11 is an oscillator generating an operating volt-
age of about 90 VAC for the EL component.
5. Interface Towards Sampling Unit
2