Kawasaki 80C51, KS152JB, 80C152 technical specifications Ale, Psen, Eben, Epsen

KS152JB Universal Communications Controller Technical Specifications

Table 1: PIN DESCRIPTION

Address Latch Enable output signal for latching the low byte of the address during

ALE

accesses to external memory.

In normal operation ALE is emitted at a constant rate of 1/6 the oscillator fre-

quency, and may be used for external timing or clocking purposes. Note, however,

that one ALE pulse is skipped during each access to external Data Memory. While

in Reset, ALE remains at a constant high level.

Program Store Enable is the Read strobe to External Program Memory. When the

PSEN

8XC152 is executing from external program memory,

is active (low). When

PSEN

the device is executing code from External Program Memory,

PSEN

is activated

twice each machine cycle, except that two

activations are skipped during

PSEN

each access to External Data Memory. While in Reset,

remains at a con-

PSEN

stant high level.

External Access enable.

must be externally pulled low in order to enable the

EA

EA

8XC152 to fetch code from External Program Memory locations 0000H to

0FFFH.

must be connected to VCC for internal program execution.

EA

EBEN

E-Bus Enable input that designates whether program memory fetches take place

via Ports 0 and 2 or ports 5 and 6. Table 2.1 shows how the ports are used in con-

junction with EBEN.

E-bus program Store Enable is the Read strobe to external program memory when

EPSEN

EBEN is high. Table 2.1 shows when

EPSEN

is used relative to

PSEN

depending

on the status of EBEN and

EA.

Kawasaki LSI USA, Inc. Page 5 of 120 Ver. 0.9 KS152JB2