DS80C320-MCG Datasheet, PDF (88/175 Pages) Dallas Semiconductor – High-Speed Microcontroller User Guide

High-Speed Microcontroller User’s Guide
Note that the first Stretch value does not follow the pattern of adding four clocks to the strobe. This is
because the first Stretch uses one clock to create additional set-up and one clock to create additional hold
time. Systems using a Stretch cycle of zero are presumed to be fast enough or to be running at a slower
clock speed. Since the Stretch is based on crystal timing, the resulting pulse widths must be viewed on
the basis of the real system timing.
DATA MEMORY CYCLE STRETCH VALUES Table 6-1
CKCON.2-0
M2
M1
M0
MEMORY
CYCLES
RD OR WR STROBE WIDTH
IN CLOCK
t @ 25 MHz
t @ 12 MHz
0
0
0
2
2
80 ns
167 ns
0
0
1
3 (default)
4
160 ns
333 ns
0
1
0
4
8
320 ns
667 ns
0
1
1
5
12
480 ns
1000 ns
1
0
0
6
16
640 ns
1333 ns
1
0
1
7
20
800 ns
1667 ns
1
1
0
8
24
960 ns
2000 ns
1
1
1
9
28
1120 ns
2333 ns
Note: These numbers represent nominal values. Actual timing may vary slightly.
FULL SPEED MOVX INSTRUCTION Figure 6-4
Last Cycle of
Previous
Instruction
First
Machine
Cycle
Second
Machine
Cycle
MOVX Instruction
Next
Instruction
Machine
Cycle
C1 C2 C3 C4 C1 C2 C3 C4 C1 C2 C3 C4 C1 C2 C3 C4
CLK
ALE
PSEN
WR
PORT 0
A0-A7
D0-D7
A0-A7
D0-D7
A0-A7
D0-D7
A0-A7
A0-A7
PORT 2
MOVX
Instruction
Address
MOVX
Instruction
Next
Instruction
Address
Next
Instruction
Read
MOVX
Data
Address
MOVX
Data
A8-A15
A8-A15
A8-A15
DATA MEMORY WRITE (2 CYCLE, STRETCH=0)
A8-A15
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