m3819 Renesas Electronics Corporation., m3819 Datasheet - Page 81

• Manufacturer Part Number: m3819
• Description: Mitsubishi 8-bit Single-chip Microcomputer 740 Family / 38000 Series
• Manufacturer: Renesas Electronics Corporation.

Table 6. Change of A-D conversion register during A-D conversion
A-D converter
A-D conversion is started by setting A-D conversion completion bit to “0”. During A-D conversion, internal operations
are performed as follows.
1. After the start of A-D conversion, A-D conversion register goes to “00
2. The highest-order bit of A-D conversion register is set to “1”, and the comparison voltage Vref is input to the
3. As a result of comparison, when Vref < V
By repeating the above operations up to the lowest-order bit of the A-D conversion register, an analog value converts
into a digital value.
A-D conversion completes at 50 clock cycles (11.9 s at f(X
conversion is stored into the A-D conversion register.
Concurrently with the completion of A-D conversion, A-D conversion interrupt request occurs, so that the A-D
conversion interrupt request bit is set to “1”.
*1 : A result of the first comparison
*3 : A result of the third comparison
*5 : A result of the fifth comparison
*7 : A result of the seventh comparison
After completion of eighth
comparator. Then, Vref is compared with analog input voltage V
Vref > V
At start of conversion
Second comparison
Third comparison
First comparison
comparison
IN
, the highest-order bit becomes “0.”
Relative formula for a reference voltage V
*1
*1
*1
Change of A-D conversion register
0
1
*2
*2 *3
A result of A-D conversion
0
0
1
When n = 0
When n = 1 to 255
0
0
0
1
IN
*2 : A result of the second comparison
*4 : A result of the fourth comparison
*6 : A result of the sixth comparison
*8 : A result of the eighth comparison
, the highest-order bit of A-D conversion register becomes “1.” When
*4
0
0
0
0
n : the value of A-D converter (decimal numeral)
*5
0
0
0
0
*6
0
0
0
0
*7
0
0
0
0
IN
) = 8.4 MHz) after it is started, and the result of the
REF
Vref = 0
Vref =
*8
0
0
0
0
IN
of A-D converter and Vref
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
.
V
256
16
REF
V
V
V
.”
REF
REF
REF
2
2
2
Value of comparison voltage (V
MITSUBISHI MICROCOMPUTERS
(n–0.5)
–
V
V
V
512
REF
REF
REF
4
4
–
0
3819 Group
V
V
512
REF
REF
8
–
ref
V
512
REF
)
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