Chart 11. 02/A0, Adsic Checksum Failure - Motorola ASTRO XTS 3000 Service Manual

Fail 02/A0
ADSIC Checksum
Use ohmmeter to electrically
verify following signal
connections to source IC:
Signal @ U406
D8-D23
A0-A2,A13-A15
PS*,RD*,WR*
SELx,RSTx
SPD,SCLK
1 VDDD,VDD1,VDD2,
VDD3
VDDAb,VDDA
VSSD,VSS1,VSS2,
VSS3
2 VSSA,VSSAb
ABI
1 Note: Finding an open at VDDx
may be difficult because of low
isolation between supply pins.
2 Also measure continuity
between GND and AGND through
jumper R510 on controller.
No
Connections
Repair opens.
Verify SPI operation
by verifying
programming of
synthesizer IC
initiated by a channel
change. If pass find
connection problems to
U406. A failure
indicates a software
problem or hardware
fault with U701.
Failure
Source
U405
U405
U405
U701
U701
+5V
+5VA
GND
AGND
R414
Verify 2.4MHz
Yes
reference clock at
good?
U406 IDC per Fig.
W10
Programming
No
signals
verified?
Verify U406-
RSTx goes high on
initial power up.
Synopsis
The ADSIC calculates a checksum of the
configuration bus data programmed
through the Host C SPI interface. This
failure indicates some problem with the
data. It should be noted that this is a
non-fatal error as it happened. As the
ADSIC controls some of the functions of
the DSP memory mapping and
interrupts, some aspects of ADSIC
programming problems may cause a
general DSP hardware failure. Some
operation of the ADSIC can be
determined by looking for the 8KHz @
IRQB. This signal is present only after
the host C has programmed the IC.
Partial operation of the device may point
to a missing supply connection. Basic
failure modes are as follows:
1) An open or short in the DSP address
or data bus and select lines may cause
an error in reading the checksum.
2) Missing or improper 2.4 MHz clock
reference.
3) Missing signal in the Host C SPI
programming interface.
4) Open or missing analog or digital
supply at one or more IC pads.
5) General IC failure.
Clock
Present?
Yes
Verify SPI
programming
signals per Fig.
W6. initiated by
mode change.
Yes
Reset high?
Yes
Replace U406.

Chart 11. 02/A0, ADSIC Checksum Failure

Verify clock at
No
ABACUS
source and/or
fix connection.
No
Replace U701.
MAEPF-26025-O
10-13