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delay tap T5
CYC-ENn/
RAS-A/
RAS-B/
RAS-C/
RAS-D/
chip address bit 0
chip address bit 1
chip address bit 2
chip address bit 3
chip address bit 4
chip address bit 5
Note: Sometimes
If the signals are not as listed, then refer tg the
schematic drawings and trace backwards to locate and correct
the problem.
"se the same setup as step C3 .
auto-jump capability, then it should be set to jump to some
address outside of the range 2000 hex through 5FFF hex (for
example, E800 hex or 0).
option at address 0, it should be disabled for this step.
With the computer power on, depress and release the reset
switch.
The processor should repeatedly execute RST 7
instructions (FF hex) from address 38 hex.
cause memory store requests to all addresses
the RST instruction stack pushes).
signals:
Signal
INSTRf T CTION-FETCH/
FETCH/
STORE/
RUNNING-REFESH/
RAS-A/
RAS-B/
RAS-C/
RAS-D/
chip write enable
CAS-A/
CAS-B/
CAS-C/
CAS-D/
Note 1: (-100ns,11T) with Z80A, '(-210ns,11T) with 8080.
Note 2: Sometimes (-225ns,11T) and sometimes
(-225ns twice,11T).
If the signals are not as listed, refer to the schematic
North Star 16K RAM BOARD
5A pin 8
8C pin
6
9A pin
4
9B pin
4
9C pin
4
9D pin
4
9A pin
5
9A pin
7
9A pin
6
9A pin
12
9A pin
11
9A pin
10
(+T,25us)
and sometimes
If the computer includes an
If the processor board has- a PROM
Location
4B pin ii
4B Pin 6
4B pin 5
6C pin 6
9 A pin 4
9B pin 4
9C pin 4
9D Pin 4
9A pin 3
9 A pin 15
9B pin 15
9C pin 15
9D pin 15
(+T,'25us)
A C ,
(-T-135ns,25us)
AC ,
(-T-40ns,25us)
AC,
(-T-40ns,25us)
AC ,
(-T-40ns,25us)
AC,
(-T-40ns,25us)
AC,
AC,
see note
AC,
see note
AC ,
see note
AC,
see note
AC,
see note
AC,
see note
(+T-90ns,25us)
This should
(resulting from
Check the following
Descr iption
AC,
(-220ns,11T)
AC, see note 1
(-220ns twice,11T)
AC,
(-260ns,11T)
AC,
AC, see note 2
AC, see note 2
AC, see note 2
AC , see note 2
AC , (-220ns twice,11T)
AC , (-210ns thrice,11T)
AC,
(-210ns thrice,11T)
AC,
(-210ns thrice,11T)
AC,
(-210ns thrice,11T)
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