AT89S51-24 ATMEL [ATMEL Corporation], AT89S51-24 Datasheet - Page 22

• Manufacturer Part Number: AT89S51-24
• Description: 8-bit Microcontroller with 4K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

External Program Memory Read Cycle
External Data Memory Read Cycle
22
AT89S51
PORT 0
PORT 2
PORT 0
PORT 2
PSEN
PSEN
ALE
ALE
RD
A0 - A7 FROM RI OR DPL
t
LHLL
t
AVLL
t
AVLL
t
P2.0 - P2.7 OR A8 - A15 FROM DPH
LHLL
t
AVWL
t
LLAX
A0 - A7
t
AVDV
t
LLAX
t
LLWL
t
t
LLPL
RLAZ
t
t
AVIV
LLDV
A8 - A15
t
PLAZ
t
RLRH
t
RLDV
DATA IN
t
t
PLIV
LLIV
INSTR IN
t
PXIX
t
PXIZ
t
t
t
RHDZ
t
A0 - A7 FROM PCL
PLPH
PXAV
t
RHDX
WHLH
A8 - A15 FROM PCH
A8 - A15
A0 - A7
INSTR IN
2487A–10/01