NEC PD17062 - Manual (Page 102)

102
µ
PD17062
10.5.6 Address Registers
The address registers are mapped to addresses 74H to 77H in the system register (at data memory addresses
74H to 7FH). They are used for program memory address operations. See Chapter 8.
The address registers can be used to manipulate data directly with data memory operation instructions.
They can also be used to transfer data via the data buffer as part of the peripheral hardware.
In other words, data can be read and written via the data buffer with PUT and GET instructions, as well as
data memory operation instructions.
Fig. 10-9 shows the relationship between the address registers and the data buffer.
Fig. 10-9 Relationship Between Address Registers and Data Buffer
DBF3
0CH
DBF2
0DH
DBF1
0EH
DBF0
0FH
b
15
b
14
b
13
b
12
b
11
b
10
b
9
b
8
b
7
b
6
b
5
b
4
b
3
b
2
b
1
b
0
b 7 b 6 b 5 b 4 b 3 b 2 b 1 b 0
0
AR 40H
Address register data write and read
0 0 0 0
F
16
Address register
b 15 b 14 b 13 b 12 b 11 b 10 b 9 b 8
0 0 0 0
0
x
F
0
0
0
0
AR3 AR2 AR1 AR0
74H 75H 76H 77H
Name
Symbol
Address
Data
Address register
x
Symbol
Peripheral
address
Peripheral hardware
Peripheral register
Name Data buffer
Symbol
Address
Bit
Data Transfer data
GET
PUT
Valid data
Name
Address
register
The eight high-order bits of the address
registers are always 0.