Epson PX-8 - Page 94

The 7508 provides signals from ports 30
through 33 as shown in Fig. 2-70. The IC 1 E
generates
the KSC pulse signals KSCO through
KSC8 according to Table 2-14.
5V
P30
P3l ~ .... __ ...
n
I
P32---- .....
P33
I
5V
< DIP Switch Assembly SW4 Setting Detection>
REV.-A
5V
2ms
n
I
n
5V
Fig. 2-70
This switch assembly forms a matrix of the KSC8 line and the KRTN lines KRTNO through KTRN7
as shown in Fig. 2-71. Thus, its setting can be read in the same way as a normal key switch.
Fig.2-71 SW4 Matrix
2-70