Agilent Technologies 4284A Service Manual page 79

Also Every time the HP 4284A turned on, the p o w e r on sequence (for example, initial-
izes the timer o n A7) is performed. T h i s p o w e r o n sequence is checked b y watching
the LED array (A7DS3, A7DS4). S e e below.
LED Pattern ( 1 = ON 0 = OFF )
Left R i g h t
1 2 3 4 5 6 7 8
X X X X X X X X
X X X X X X X X
1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0
0 1 0 0 0 0 0 0
0 0 1 0 0 0 0 0
0 0 0 1 0 0 0 0
0 0 0 0 1 0 0 0
0 0 0 0 0 0 1 0
0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
0 1 0 0 0 0 0 0
1 1 0 0 0 0 0 0
0 0 1 0 0 0 0 0
1 0 1 0 0 0 0 0
0 1 1 0 0 0 0 0
1 1 1 0 0 0 0 0
0 0 0 1 0 0 0 0
1 0 0 1 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
Task
Clears memory card read/write flip-flop
Turns off memory card power supply
LED test
LED test
LED test
LED test
LED test
LED test
LED test
LED test
LED test
Initializes LCD controller
Initializes timer on A7
Initializes timer on A90
Initializes A90
Check the bit switch (A7S3)
Initializes timer on the A-D converter
Initializes PIA chip on A30 or A31
Initializes PIA chip on A40
Clears all interrupt signal
RAM read/write test
Clears RAM
Displays "Copyright" message
ROM check sum test
EEPROM check sum test
EEPROM check sum test for A40 (Option 301 only)
Starts the measurement
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