Data bit, Function, Hex data – Fluke Biomedical 942A-200L-M4 User Manual
Page 29: Position
Theory of Operation
Main Circuit Board
2
2-15
The following paragraphs describe the operation of each of these registers.
Data Entry (Read Only)
Octal buffer U36 functions as an interface to supply the status of the switches for data entry to the internal
data bus address (4002). The data entry read functions are shown in Table 2-12. The function switch
logic is shown in Table 2-13.
Table 2-12. Data Entry Read Functions
Data Bit
Function
D0
Enter Switch (Active Low)
D1
Value Select Switch (Active Low)
D2
Digit Select Switch (Active Low)
D3 (Not
Used)
D4
D4 – D7 (16 position function switch,
D5
see Table 2-11.)
D6 (Not
Used)
D7 (Not
Used)
Table 2-13. Function Switch Logic
Hex Data
D7
D6
D5
D4
Position
Function
F 1
1
1
1 0
High
E 1
1
1
0 8
Calibrate
Mode
D 1
1
0
1 1
Warn
C 1
1
0
0 9
Undefined
B 1
0
1
1 4
Overrange
A 1
0
1
0 C
Undefined
9 1
0
0
1 5
Calibration
Constant
8 1
0
0
0 D
Undefined
7 0
1
1
1 2
Resolving
Time
6 0
1
1
0 A
Undefined
5
0
1
0
1
3
Full Scale Value
4 0
1
0
0 B
Undefined
3 0
0
1
1 6
Background
Subtract
2 0
0
1
0 E
Undefined
1
0
0
0
1
7
Low Scale Value
0 0
0
0
0 F
Undefined