XC886/888CLM
Processor Architecture
User’s Manual
2-8
V1.3, 2010-02
Processor Architecture, V 1.0
Figure 2-2
CPU Instruction Timing
Instructions are 1, 2 or 3 bytes long as indicated in the “Bytes” column of
the XC886/888, the time taken for each instruction includes:
•
decoding/executing the fetched opcode
•
fetching the operand/s (for instructions > 1 byte)
•
fetching the first byte (opcode) of the next instruction (due to XC886/888 CPU
pipeline)
f
CCLK
C1P1
C1P2
Read next opcode
(without wait state)
C1P1
C1P2
(a) 1-byte, 1-cycle instruction, e.g. INC A
WAIT
WAIT
Read next opcode
(one wait state)
C1P1
C1P2
Read next opcode
(without wait state)
C1P1
C1P2
(b) 2-byte, 1-cycle instruction, e.g. ADD A, #data
WAIT
WAIT
Read next opcode
(one wait state)
Read 2
nd
byte
(without wait state)
WAIT
WAIT
Read 2
nd
byte
(one wait state)
C1P1
C1P2
C1P1
C1P2
WAIT
C2P1
C2P2
Read next opcode
(without wait state)
C2P1
WAIT
C2P2
Read next opcode
(one wait state)
(c) 1-byte, 2-cycle instruction, e.g. MOVX
next instruction
next instruction
next instruction
next instruction
next instruction
next instruction
*