41
MB90650A Series
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
MD1
MD0
ANS2
ANS1
ANS0
ANE2
ANE1
ANE0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Initial value
Initial value
Initial value
Initial value
00000000
B
Control status register 1 (ADCS1)
BUSY
INT
INTE
PAUS
STS1
STS0
STRT
DA
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
00000000
B
Control status register 2 (ADCS2)
7
6
5
4
3
2
1
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
XXXXXXXX
B
Data register 1 (ADCR1)
—
—
—
—
—
—
9
8
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
XXXXXXXX
B
Data register 2 (ADCR2)
R
X
: Readable and writable
: Read only
: Indeterminate
ADCS2
ADCR2
ADCR1
ADCS1
8 bits
bit 15
bit 8 bit 7
bit 0
8 bits
Address : 000036
H
Address : 000037
H
Address : 000038
H
Address : 000039
H
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R/W