Datasheet

Philips Semiconductors Product data
P80C3xX2; P80C5xX2;
P87C5xX2
80C51 8-bit microcontroller family
4K/8K/16K/32K ROM/OTP, low voltage (2.7 to 5.5 V),
low power, high speed (30/33 MHz)
2003 Jan 24
11
PIN NUMBER
MNEMONIC NAME AND FUNCTIONTYPETSSOPLQFPPLCCDIP
PSEN 29 32 26 18 O Program Store Enable: The read strobe to external program memory. When the
device is 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/V
PP
31 35 29 20 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 0000H to
0FFFH/1FFFH/3FFFH/7FFFH. If EA is held high, the device executes from internal program memory
unless the program counter contains an address greater than the on-chip ROM/OTP. This pin also
receives the 12.75 V programming supply voltage (V
PP
) during EPROM programming. If security bit
1 is programmed, EA will be internally latched on Reset.
XTAL1 19 21 15 8 I Crystal 1: Input to the inverting oscillator amplifier and input to the internal clock
generator circuits.
XTAL2 18 20 14 7 O Crystal 2: Output from the inverting oscillator amplifier.
NOTES:
To avoid “latch-up” effect at power-on, the voltage on any pin at any time must not be higher than V
CC
+ 0.5 V or V
SS
– 0.5 V, respectively.
1. Absent in the TSSOP38 package.