Datasheet

Section 2 CPU
Rev. 8.00 Mar. 09, 2010 Page 72 of 658
REJ09B0042-0800
To avoid this problem, store a copy of the PCR3 data in a work area in memory. Perform the bit
manipulation on the data in the work area, then write this data to PCR3.
[A: Prior to executing BCLR]
MOV. B #3F, R0L The PCR3 value (H'3F) is written to a work area in memory
MOV. B R0L, @RAM0 (RAM0) as well as to PCR3.
MOV. B R0L, @PCR3
P3
7
P3
6
P3
5
P3
4
P3
3
P3
2
P3
1
P3
0
Input/output Input Input Output Output Output Output Output Output
Pin state Low level High level Low level Low level Low level Low level Low level Low level
PCR3 0 0 1 1 1 1 1 1
PDR3 1 0 0 0 0 0 0 0
RAM0 0 0 1 1 1 1 1 1
[B: BCLR instruction executed]
BCLR #0 , @RAM0 The BCLR instruction is executed designating the PCR3
work area (RAM0).
[C: After executing BCLR]
MOV. B @RAM0, R0L The work area (RAM0) value is written to PCR3.
MOV. B R0L, @PCR3
P3
7
P3
6
P3
5
P3
4
P3
3
P3
2
P3
1
P3
0
Input/output Input Input Output Output Output Output Output Output
Pin state Low level High level Low level Low level Low level Low level Low level High level
PCR3 0 0 1 1 1 1 1 0
PDR3 1 0 0 0 0 0 0 0
RAM0 0 0 1 1 1 1 1 0
Table 2.12 lists the pairs of registers that share identical addresses. Table 2.13 lists the registers
that contain write-only bits.