
MB90630A Series
39
4. A/D Converter
The A/D converter converts analog input voltages to digital values. The A/D converter has the following features.
Conversion time: Minimum of 5.2
μ
s per channel (for a 16 MHz machine clock)
Uses RC-type successive approximation conversion with a sample and hold circuit.
10-bit resolution
Eight program-selectable analog input channels
Single conversion mode
: Selectively convert a one channel.
Scan conversion mode
: Continuously convert multiple channels. Maximum of 8 program-
selectable channels.
Continuous conversion mode
: Repeatedly convert specified channels.
Stop conversion mode
: Convert one channel then halt until the next activation. (Enables
synchronization of the conversion start timing.)
An A/D conversion completion interrupt request to the CPU can be generated on the completion of A/D
conversion. This interrupt can activate I
2
OS to transfer the result of A/D conversion to memory and is suitable
for continuous operation.
Activation by software, external trigger (falling edge), or timer (rising edge) can be selected.
(1) Register Configuration
The A/D converter has the following registers.
8 bits
8 bits
ADCS2
ADCR2
ADCS1
ADCR1
15
8
7
0
MD1
MD0
ANS2
ANS1
ANS0
ANE2
ANE1
ANE0
7
6
5
4
3
2
1
0
BUSY
INT
INTE
PAUS
STS1
STS0
STRT
DA
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
—
—
—
—
—
—
9
8
15
14
13
12
11
10
9
8
Address: 000036
H
Address: 000037
H
Address: 000038
H
Address: 000039
H
bit
bit
bit
bit
Control status register
(ADCS1, ADCS2)
Data register
(ADCR1, ADCR2)