AT89C51RE2 Atmel Corporation, AT89C51RE2 Datasheet - Page 50

• Manufacturer Part Number: AT89C51RE2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RE2

• Flash (kbytes): 128 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Spi: 1
• Uart: 2
• Sram (kbytes): 8.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART/OCD
• Watchdog: Yes

Operation Cross Memory Access
Sharing Instructions
50
AT89C51RE2
Space addressable in read and write are:
•
•
•
•
•
•
•
•
The table below provide the different kind of memory which can be accessed from different code
location.
Table 27. Cross Memory Access
Table 28. Instructions shared
Note:
Action
or BANK3
boot RM0
External
Read
Write
memory
EA = 0
RAM
ERAM (Expanded RAM access by movx)
XRAM (eXternal RAM)
FM0 (user flash)
Hardware byte
XROW FM0
Boot RM0
Flash Column latch
FM0
by cl: using Column Latch
RAM
Action
MOV
MOV
Read
Read
Read
Write
Write
Write
RAM
A,@DPTR
@DPTR,A
ok
ok
ok
ok
ok
ok
XRAM
MOVX
MOVX
XRAM
ERAM
ok
ok
ok
ok
ok
ok
@A+DPTR
MOVC A,
RM0
boot RM0
-
ok
-
-
-
-
-
@DPTR,A
CL FM0
MOVX
ok (RWW)
ok (idle)
-
FM0
ok
ok
-
-
@A+DPTR
MOVC A,
FM0
by CL
ok (RWW)
FM0
HSB
ok
ok
ok
-
-
@A+DPTR
MOVC A,
ok (RWW)
HSB
by CL
FM0
FCB
ok
ok
ok
-
-
7663E–8051–10/08
XAF FM0
@A+DPTR
XAF FM0
ok (RWW)
MOVC A,
by CL
FM0
ok
ok
ok
-
-