KS152JB Universal Communications ControllerTechnical Specifications
Kawasaki LSI USA, Inc. Page 5 of 120 Ver. 0.9 KS152JB2
ALE Address Latch Enable output signal for latching the low byte of the address during
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.
PSEN Program Store Enable is the Read strobe to External Program Memory. When the
8XC152 is executing from external program memory,PSEN is active (low). When
the device is executing code from External Program Memory,PSEN is activated
twice each machine cycle, except that two PSEN activations are skipped during
each access to External Data Memory. While in Reset, PSEN remains at a con-
stant high level.
EA External Access enable. EA must be externally pulled low in order to enable the
8XC152 to fetch code from External Program Memory locations 0000H to
0FFFH.
EA must be connected to VCC for internal program execution.
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.
EPSEN E-bus program Store Enable is the Read strobe to external program memory when
EBEN is high. Table 2.1 shows whenEPSEN is used relative to PSEN depending
on the status of EBEN and EA.
Table 1: PIN DESCRIPTION