411
13.2 Register Descriptions
13.2.1 A/D Data Registers A to D (ADDRA to ADDRD)
Bit
ADDRn
Initial value
14
AD8
0
R
12
AD6
0
R
10
AD4
0
R
8
AD2
0
R
6
AD0
0
R
0
—
0
R
4
—
0
R
2
—
0
R
15
AD9
0
R
13
AD7
0
R
11
AD5
0
R
9
AD3
0
R
7
AD1
0
R
1
—
0
R
5
—
0
R
3
—
0
R
A/D conversion data
10-bit data giving an
A/D conversion result
Reserved bits
Read/Write
(n = A to D)
The four A/D data registers (ADDRA to ADDRD) are 16-bit read-only registers that store the
results of A/D conversion.
An A/D conversion produces 10-bit data, which is transferred for storage into the A/D data
register corresponding to the selected channel. The upper 8 bits of the result are stored in the upper
byte of the A/D data register. The lower 2 bits are stored in the lower byte. Bits 5 to 0 of an A/D
data register are reserved bits that always read 0. Table 13-3 indicates the pairings of analog input
channels and A/D data registers.
The CPU can always read the A/D data registers. The upper byte can be read directly, but the
lower byte is read through a temporary register (TEMP). For details see section 13.3, CPU
Interface.
The A/D data registers are initialized to H'0000 by a reset and in standby mode.
Table 13-3 Analog Input Channels and A/D Data Registers
Analog Input Channel
Group 0
Group 1
A/D Data Register
AN
0
AN
4
ADDRA
AN
1
AN
5
ADDRB
AN
2
AN
6
ADDRC
AN
3
AN
7
ADDRD
