Motorola ASTRO Digital Saber User Manual

10-9
Chart 13 . 02/88, DSP External SRAM Failure U414
R3SEL*
appears
functional?
Yes
Replace U414.
Do all three
SRAMs
exhibit a
fault?
Replace U405.
Yes
MAEPF-24410-A
No
No
ADSIC
checksum
error?
Refer to
section on
FAIL 02/A0.
Chart C.11
Yes
No
During power
up Self-Test
verify E1~ on
U414 is enabled
by high to low
transitions of
R3SEL*.
During power-up
verify operation
of U415 by
looking for
transitions on
inputs IN_B and
IN_A.
Inputs to
U415
functional?
Replace U415.
Replace U405.
Yes
No
Synopsis
On power-up the DSP writes
data to the device and then
verifies the data. This failure
indicates the DSP SRAM failed
this pattern/checksum test.
U414 is selected by the DSP
(U405) address bus with the
addition of the OR logic gate
U415. Basic failure modes
are as follows:
1) Some problem exists
(open/shorts) with the
external address/data bus.
2) Possible failure of the DSP
address/data bus or
RD*/WR*/PS*/DS* signals
used in selecting this part.
Since the other two DSP
SRAMs share this bus as well
as other ICs, this is not a likely
failure.
3) Operational failure of the OR
logic of gate U415.
3) Open in supply or ground to
the IC.
4) Failure of the IC.
Fail 02/88
DSP SRAM U414
Failure
Use ohmmeter to
electrically verify
following signal connections
to source IC:
Signal @ U414 Source
D0-D23 U405
A0-A12 U405
WR*,RD* U405
E1* U415-OUT
E2 U406-A15
X/Y*,V/S* GND
VCC +5V
VSS GND
Signal @ U415 Source
IN_A U405-A14
IN_B U405-A13
Connections
good?
Repair opens.
Yes
No
Check for
ADSIC
programming
checksum
error.
Chart 14 . 02/84, DSP External SRAM Failure U403
Fail 02/84
DSP SRAM U403
Failure
Synopsis
On power-up the DSP writes
data to the device and then
verifies the data. This failure
indicates the DSP SRAM failed
this pattern/checksum test.
Besides utiling decoding logic
from the DSP (U405), U403
has additional logic in the form
of RSEL from the ADSIC
(U406). A problem with the
ADSIC in the form of a
programming or hardware fault
will cause a problem with the
operation of this part. Basic
failure modes are as follows:
1) Some problem exists
(open/shorts) with the
external address/data bus.
2) Some problem exists with
the ADSIC memory select
(RSEL) which may include an
ADSIC programming problem
(SPI bus) or possibly a failed
ADSIC.
3) Possible failure of the DSP
address/data bus or
RD*/WR*/PS*/DS* signals
used in selecting this part.
Since the other two DSP
SRAMs share this bus as well
as other ICs, this is not a likely
failure.
4) Open in supply or ground to
the IC.
5) Failure of the IC.
Use ohmmeter to
electrically verify
following signal connections
to source IC:
Signal @ U403 Source
D0-D23 U405
A0-A12 U405
WR*,RD* U405
E1* U405-A15
E2 U406-RSEL
X/Y*,V/S* GND
VCC +5V
VSS GND
RSEL
appears
functional?
Yes
Replace
U406.
Replace U403.
Do all three
SRAMs
exhibit a
fault?
Replace U405.
MAEPF-24409-B
Yes
No
No
Connections
good?
Repair opens.
Yes
No
Check for
ADSIC
programming
checksum
error.
ADSIC
checksum
error?
Refer to
section on
FAIL 02/A0.
Chart C.11
Yes
No
During power
up Self-Test
verify E2 on
U403 is enabled
by low to high
transitions of
RSEL.

Motorola ASTRO Digital Saber Specifications

General

Brand	Motorola
Model	ASTRO Digital Saber
Category	Portable Radio
Language	English