Direct Page Register (Dpr); Fig. 2.26 Direct Page Register (Dpr) Setting And Data Access Example - Fujitsu MB90420/5 (A) Series Hardware Manual

MB90420/5 (A) SERIES F

2.7.8 Direct Page Register (DPR)

The direct page register (DPR) is an 8-bit register to specify bit 8 to bit 15 (address 8 to address 15) of the
operand address when executing the instruction using the abbreviated direct addressing.
n Direct page register (DPR)
The DPR specifies bit 8 to bit 15 (addr8 to addr15) of the operand address when executing the instruction
using abbreviated direct addressing (Figure 2.25). The DPR is 8-bit length, and is initialized to 01
reset. Also, the DPR can be read and written by an instruction.
DTB register
AAAAAAAA
24-bit physical address
MSB : Most Significant Bit
LSB : Least Significant Bit
Fig. 2.25 Generation of Physical Addressing in Direct Page Register (DPR)
Figure 2.26 shows the direct page register (DPR) setting and an example of data access.
MOV S: 56 , #5A
H
DTB Register
DPR Register
MSB : Most Significant Bit
LSB : Least Significant Bit

Fig. 2.26 Direct Page Register (DPR) Setting and Data Access Example

2
MC-16LX FAMILY 16-BIT MICROCONTROLLERS HARDWARE MANUAL
MSB
AAAAAAAA
bit 24 bit 16
H
12
H
34
H
DPR register
BBBBBBBB
BBBBBBBB
bit 15 bit 8 bit 7
Result obtained by executing instruction
123458
H
123456
H
123454
H
MSB
2-26
Direct address during
instruction
CCCCCCCC
LSB
CCCCCCCC
bit 0
Upper 8 bits Lower 8 bits
5A
H
by a
H
LSB