Reset - Epson PX-8 Technical Manual

REV.-A
2.6 Reset
The reset signal initializes the computer circuit and is used to prevent any abnormal operation at
power on (during the logic circuit power voltage rise time), after emergency shut-down due to
any computer abnormality, and before subsequent restart. The resetting operation of this com-
puter is accomplished indirectly by software. The sub-CPU internal program differs from other
computers, which are reset directly by a switch operation.
Fig. 2-63 outlines the RESET signal circuits.
System reset
signal
VB
SW2
SW5
~ SWr-~P~6~0~--'P~0~0~-----RS~~
(INTO)
o>--....:;>~ VB
INITIAL
Z80-related
Reset routine
(ADSNS)
I
Internal
.....
Q)
c::
co·';:::;
o
~
LO
e
,-.....
...
Q)
<J)
Q)
RESETSW
Sub-CPU
I E - - -
7508 (2E)
Clears all registers ~_ a::
GAH40D
(6A)
~
-.£'
1:
A A A
RST
I
such as timer, etc.
ltr
Data
I
nes
o
to 7
RSO
L~
-
Z-80
RS
(4A)
-
6303
RS
(13D)
GAH40M
(4C)
CN8
7B~7
(Option unit i nterface)
-
82C51
P71
~---IOFF
GAH40M
~-----IOFF GAH40D
'--------=;;.
CN 8
(Option unit interface)
Fig. 2-63 Reset Signal Circuit Block Diagram
2-63
Gate array
OFF signal