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HARDWARE
FUNCTION BLOCK OPERATIONS
(15) Notes for the use of A-D conversion 2
Do not change the operating mode (both A-D conversion mode and
comparator mode) of A-D converter with bit 3 of register Q2 while
A-D converter is operating.
When the operating mode of A-D converter is changed from the
comparator mode to A-D conversion mode with the bit 3 of register
Q2, note the following;
• Clear bit 2 of register V2 to "0" to change the operating mode of
the A-D converter from the comparator mode to A-D conversion
mode with the bit 3 of register Q2.
• The A-D conversion completion flag (ADF) may be set when the
operating mode of the A-D converter is changed from the com-
parator mode to the A-D conversion mode. Accordingly, set a
value to register Q2, and execute the SNZAD instruction to clear
the ADF flag.
Output data
1023
1022
Zero transition voltage (V
Fig. 30 Definition of A-D conversion accuracy
Vn: Analog input voltage when the output data changes from "n" to "n+1" (n = 0 to 1022)
• 1LSB at relative accuracy
• 1LSB at absolute accuracy
1-46
Full-scale transition voltage (V
Differential non-linearity error =
c
Linearity error =
[LSB]
a
n+1
n
Actual A-D conversion
characteristics
a: 1LSB by relative accuracy
b: V
–V
n+1
n
c: Difference between ideal V
and actual V
n
Ideal line of A-D conversion
between V
1
0
V
V
0
1
)
0T
V
–V
FST
0T
(V)
1022
V
DD
(V)
1024
4513/4514 Group User's Manual
(16) Definition of A-D converter accuracy
The A-D conversion accuracy is defined below (refer to Figure 30).
• Relative accuracy
Zero transition voltage (V
This means an analog input voltage when the actual A-D con-
version output data changes from "0" to "1."
Full-scale transition voltage (V
This means an analog input voltage when the actual A-D con-
version output data changes from "1023" to "1022."
Linearity error
This means a deviation from the line between V
a converted value between V
Differential non-linearity error
This means a deviation from the input potential difference re-
quired to change a converter value between V
LSB at the relative accuracy.
• Absolute accuracy
This means a deviation from the ideal characteristics between 0
to V
of actual A-D conversion characteristics.
DD
)
FST
b–a
[LSB]
a
b
a
c
n
–V
0
1022
V
V
n
n+1
)
0T
)
FST
and V
.
0T
FST
V
V
1022
DD
Analog voltage
and V
of
0T
FST
and V
by 1
0T
FST
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