Hitachi H8/3664 Hardware Manual page 61

To avoid this problem, store a copy of the PDR5 data in a work area in memory. Perform the bit
manipulation on the data in the work area, then write this data to PDR5.
[A: Prior to executing BSET]
MOV.B #80,
MOV.B R0L,
MOV.B R0L,
P5
Input/output Input
Pin state Low
level
PCR5 0
PDR5 1
RAM0 1
[B: BSET instruction executed]
BSET #0,
[C: After executing BSET]
MOV.B @RAM0, R0L
MOV.B R0L,
P5
Input/output Input
Pin state Low
level
PCR5 0
PDR5 1
RAM0 1
R0L
The PDR5 value (H'80) is written to a work area in
@RAM0
memory (RAM0) as well as to PDR5.
@PDR5
P5 P5
7 6
Input Output
High Low
level level
0 1
0 0
0 0
@RAM0
The BSET instruction is executed designating the PDR5
work area (RAM0).
The work area (RAM0) value is written to PDR5.
@PDR5
P5 P5
7 6
Input Output
High Low
level level
0 1
0 0
0 0
P5 P5
5 4
Output Output
Low Low
level level
1 1
0 0
0 0
P5 P5
5 4
Output Output
Low Low
level level
1 1
0 0
0 0
P5 P5
3 2
Output Output
Low Low
level level
1 1
0 0
0 0
P5 P5
3 2
Output Output
Low Low
level level
1 1
0 0
0 0
P5
1 0
Output
Low
level
1
0
0
P5
1 0
Output
High
level
1
1
1
45