P87C660X2 PHILIPS [NXP Semiconductors], P87C660X2 Datasheet - Page 8

• Manufacturer Part Number: P87C660X2
• Description: 80C51 8-bit microcontroller family
• Manufacturer: PHILIPS [NXP Semiconductors]

1. To avoid “latch-up” effect at power-on, the voltage on any pin (other than EA) must not be higher than V
2. The pins are designed for test mode also.
Philips Semiconductors
NOTE:
2003 Oct 02
ALE
PSEN
EA
XTAL1
XTAL2
MNEMONIC
MNEMONIC
80C51 8-bit microcontroller family
RAM, low voltage (2.7 to 5.5 V), low power, high speed (30/33
MHz), two 400KB I
2
2
2
PLCC
PIN NUMBER
33
32
35
21
20
2
C interfaces
LQFP
27
26
29
15
14
TYPE
TYPE
O
O
O
I
I
16 KB OTP/ROM, 512B
Address Latch Enable: Output pulse for latching the LOW byte of the address
during an access to external memory. In normal operation, ALE is emitted twice
every machine cycle, and can be used for external timing or clocking. Note that one
ALE pulse is skipped during each access to external data memory. ALE can be
disabled by setting SFR auxiliary.0. With this bit set, ALE will be active only during a
MOVX instruction.
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. 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
(V
Crystal 1: Input to the inverting oscillator amplifier and input to the internal clock
generator circuits.
Crystal 2: Output from the inverting oscillator amplifier.
PP
) during programming.
8
NAME AND FUNCTION
NAME AND FUNCTION
CC
P8xC660X2/661X2
+ 0.5 V or less than V
Product data
SS
– 0.5 V.