P87C51FA Philips Semiconductors, P87C51FA Datasheet - Page 6

• Manufacturer Part Number: P87C51FA
• Description: 80C51 8-bit microcontroller family 8K.64K/256.1K OTP/ROM/ROMless/ low voltage 2.7V.5.5V/ low power/ high speed 33 MHz
• Manufacturer: Philips Semiconductors

Philips Semiconductors
PIN DESCRIPTIONS (Continued)
NOTE:
To avoid “latch-up” effect at power-on, the voltage on any pin at any time must not be higher than V
2000 Aug 07
PSEN
EA/V
XTAL1
XTAL2
MNEMONIC
80C51 8-bit microcontroller family
8K–64K/256–1K OTP/ROM/ROMless, low voltage (2.7V–5.5V),
low power, high speed (33 MHz)
PP
DIP
29
31
19
18
PIN NUMBER
LCC
32
35
21
20
QFP
26
29
15
14
TYPE NAME AND FUNCTION
O
O
I
I
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.
External Access Enable/Programming Supply Voltage: EA must be externally held low
to enable the device to fetch code from external program memory locations starting with
0000H. If EA is held high, the device executes from internal program memory unless the
program counter contains an address greater than 8k Devices (IFFFH), 16k Devices
(3FFFH) or 32k Devices (7FFFH). Since the RD+ has 64k Internal Memory, the RD+ will
execute only from internal memory when EA is held high. This pin also receives the 12.75 V
programming supply voltage (V
programmed, EA will be internally latched on Reset.
Crystal 1: Input to the inverting oscillator amplifier and input to the internal clock generator
circuits.
Crystal 2: Output from the inverting oscillator amplifier.
6
PP
) during EPROM programming. If security bit 1 is
8XC51RA+/RB+/RC+/RD+/80C51RA+
CC
+ 0.5 V or V
8XC51FA/FB/FC/80C51FA
SS
– 0.5 V, respectively.
Product specification
8XC54/58