at89c51-12qi ATMEL Corporation, at89c51-12qi Datasheet - Page 12

• Manufacturer Part Number: at89c51-12qi
• Description: 8-bit Microcontroller With 4k Bytes Flash
• Manufacturer: ATMEL Corporation

External Program Memory Read Cycle
External Data Memory Read Cycle
12
PORT 0
PORT 2
PORT 0
PORT 2
PSEN
PSEN
ALE
ALE
RD
A0 - A7 FROM RI OR DPL
AT89C51
t
LHLL
t
AVLL
t
AVLL
t
P2.0 - P2.7 OR A8 - A15 FROM DPH
LHLL
t
AVWL
t
LLAX
t
AVDV
A0 - A7
t
LLAX
t
LLWL
t
t
RLAZ
LLPL
t
t
LLDV
AVIV
A8 - A15
t
PLAZ
t
RLRH
t
RLDV
DATA IN
t
t
PLIV
LLIV
INSTR IN
t
PXIX
t
PXIZ
t
RHDZ
t
A0 - A7 FROM PCL
t
t
t
RHDX
PLPH
PXAV
WHLH
A8 - A15 FROM PCH
A8 - A15
A0 - A7
INSTR IN