DS89C420 Dallas Semiconducotr, DS89C420 Datasheet - Page 24

• Manufacturer Part Number: DS89C420
• Description: Ultra-High-Speed Microcontroller
• Manufacturer: Dallas Semiconducotr

Figure 5. Non-Page Mode, External Data-Memory Access (Stretch = 0,
CD1:CD2 = 10)
Figure 6. Non-Page Mode, External Data-Memory Access (Stretch = 1,
CD1:CD2 = 10)
RD WR
RD WR
XTAL1
XTAL1
Port 0
Port 2
Port 0
Port 2
PSEN
PSEN
ALE
ALE
MOVX
Instruction
Fetch
MOVX
Instruction
Fetch
A
A
A
A
MOVX
MOVX
1st Machine Cycle
1st Machine Cycle
A
A
MOVX Instruction
INST
INST
MOVX Instruction
2nd Machine Cycle
2nd Machine Cycle
24 of 59
Memory
Access
Stretch = 0
A
A
A
A
Memory Access
Stretch = 1
DATA
DATA
3rd Machine Cycle