
6
4428E–8051–02/08
AT/TS80C31X2
EA
31
35
29
I
External Access Enable: EA must be externally held low to enable the device to
fetch code from external program memory locations.
XTAL1
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