Datasheet

12
AT89C51RB2/RC2
4180D–8051–06/05
PSEN 29 32 26 O Program Strobe Enable: The read strobe to external program memory. When
executing code from the external program memory, PSEN
is activated twice each
machine cycle, except that two PSEN
activations are skipped during each access to
external data memory. PSEN
is not activated during fetches from internal program
memory.
EA 31 35 29 I External Access Enable: EA
must be externally held low to enable the device to
fetch code from external program memory locations 0000H to FFFFH (RD). If
security level 1 is programmed, EA
will be internally latched on Reset.
Table 12. Pin Description for 40 - 44 Pin Packages (Continued)
Mnemonic
Pin Number
Type Name and FunctionDIL LCC VQFP44 1.4