Datasheet

55
AT89C51CC03
4182O–CAN–09/08
Operation Cross Memory Access
Space addressable in read and write are:
•RAM
• ERAM (Expanded RAM access by movx)
• XRAM (eXternal RAM)
• EEPROM DATA
• FM0 ( user flash )
• Hardware byte
•XROW
•Boot Flash
• Flash Column latch
The table below provide the different kind of memory which can be accessed from differ-
ent code location.
Note: 1. RWW: Read While Write
Table 18. Cross Memory Access
Action RAM
XRAM
ERAM Boot FLASH FM0 E² Data
Hardware
Byte XROW
boot FLASH
Read OK OK OK OK -
Write - OK
(1)
OK
(1)
OK
(1)
OK
(1)
FM0
Read OK OK OK OK -
Write - OK (idle) OK
(1)
-OK
External memory
EA = 0
or Code Roll Over
Read - - OK - -
Write - - OK
(1)
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