Table of Contents
Advertisement
11
A-D1 Successive Approximation Register (AD1SAR)
D0
1
2
D
Bit Name
0-5
No functions assigned
6-15
AD1SAR
(A-D1 successive approximation
value/comparison value)
Note: This register must always be accessed in halfwords.
The A-D1 Successive Approximation Register (AD1SAR), when in A-D conversion mode, is used
to read out the conversion result of the A-D1 converter, and when in comparator mode, it is used to
write a comparison value.
In A-D conversion mode, the successive approximation method is used to perform A-D conversion.
With this method, the reference voltage VREF and analog input voltages are sequentially
compared bitwise beginning with the high-order side, and the comparison result is set in the A-
D1Successive Approximation Register (AD1SAR) bits (D6-D15). After the A-D conversion is
completed, the value of this register is transferred to the 10-bit A-D1 Data Register (AD1DTn)
corresponding to the converted channel. When you read this register in the middle of A-D
conversion, you see the result in the middle of conversion.
In comparator mode, write a comparison value (the value to be compared in comparate operation)
to this register. Simultaneously with a write to this register, comparate operation with the analog
input pin that has been set by Single Mode Register 1 starts. After comparate operation, the result
is stored in the A-D1 Comparate Data Register (AD1CMP).
Use the calculation formula shown below to find the comparison value to be written to the A-
D1Successive Approximation Register (AD1SAR) during comparator mode.
Comparison value = H'3FF ×
3
4
5
6
7
11-34
11.2 A-D Converter Related Registers
<Address: H'0080 0A88>
8
9
10
11
AD1SAR
Function
• A-D successive approximation value
(A-D conversion mode)
• Comparison value (comparator mode)
Comparate comparison voltage [V]
VREF1 input voltage [V]
A-D CONVERTERS
12
13
14
D15
<When reset:Indeterminate>
R
W
0
–
Ver.0.10
Advertisement
Table of Contents
