3069RF-ZTAT Datasheet, PDF (62/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER

Operation field only
op
NOP, RTS, etc.
Operation field and register fields
op
rn
rm
ADD.B Rn, Rm, etc.
Operation field, register fields, and effective address extension
op
rn
rm
EA (disp)
MOV.B @(d:16, Rn), Rm
Operation field, effective address extension, and condition field
op
cc
EA (disp)
Figure 2.9 Instruction Formats
BRA d:8
2.6.5 Notes on Use of Bit Manipulation Instructions
The BSET, BCLR, BNOT, BST, and BIST instructions read a byte of data, modify a bit in the
byte, then write the byte back. Care is required when these instructions are used to access registers
with write-only bits, or to access ports.
Step
1
2
3
Read
Modify
Write
Description
Read one data byte at the specified address
Modify one bit in the data byte
Write the modified data byte back to the specified address
Example 1: BCLR is executed to clear bit 0 in the port 4 data direction register (P4DDR) under
the following conditions.
P4₇, P4₆: Input pins
P4₅ – P4₀: Output pins
The intended purpose of this BCLR instruction is to switch P4₀ from output to input.
Before Execution of BCLR Instruction
Input/output
DDR
P4₇
Input
0
P4₆
Input
0
P4₅
Output
1
P4₄
Output
1
P4₃
Output
1
P4₂
Output
1
P4₁
Output
1
P4₀
Output
1
Rev. 5.0, 09/04, page 40 of 978