P89C51RB2 Просмотр технического описания (PDF) - Philips Electronics

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производитель

P89C51RB2

80C51 8-bit Flash microcontroller family 16KB/32KB/64KB ISP/IAP Flash with 512B/512B/1KB RAM

Philips Electronics 

Philips Semiconductors

80C51 8-bit Flash microcontroller family

16KB/32KB/64KB ISP/IAP Flash with 512B/512B/1KB RAM

Product data

P89C51RB2/P89C51RC2/

P89C51RD2Hxx

PIN NUMBER

MNEMONIC

PDIP PLCC LQFP

TYPE

NAME AND FUNCTION

PSEN

29

32

26

O Program Store 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/VPP

XTAL1

31

35

29

I External Access Enable/Programming Supply Voltage: EA must be externally

held low to enable the device to fetch code from external program memory

locations. If EA is held high, the device executes from internal program memory.

The value on the EA pin is latched when RST is released and any subsequent

changes have no effect. This pin also receives the programming supply voltage

(VPP) during Flash programming.

19

21

15

I Crystal 1: Input to the inverting oscillator amplifier and input to the internal clock

generator circuits.

XTAL2

18

20

14

O Crystal 2: Output from the inverting oscillator amplifier.

NOTE:

To avoid “latch-up” effect at power-on, the voltage on any pin (other than VPP) must not be higher than VCC + 0.5 V or less than VSS – 0.5 V.

2002 May 24

6

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