P89C668 Philips Semiconductors, P89C668 Datasheet - Page 6

• Manufacturer Part Number: P89C668
• Description: 80C51 8-bit Flash microcontroller family 64KB ISP FLASH with 8KB RAM
• Manufacturer: Philips Semiconductors

Philips Semiconductors
NOTE:
To avoid “latch-up” effect at power-on, the voltage on any pin (other than V
2001 Jul 27
EA/V
XTAL1
XTAL2
MNEMONIC
MNEMONIC
80C51 8-bit Flash microcontroller family
64KB ISP Flash with 8KB RAM
PP
PLCC
PIN NUMBER
35
21
20
LQFP
29
15
14
O
I
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. Since the P89C668 has 64k internal
memory, the P89C668 will execute only from internal memory when EA is held high. 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.
6
PP
) must not be higher than V
NAME AND FUNCTION
NAME AND FUNCTION
PP
) during Flash programming.
CC
+ 0.5 V or less than V
P89C668
Preliminary data
SS
– 0.5 V.