Bootstrap Fail - Motorola ASTRO Digital Spectra Plus Service Manual
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5-6
Isolate and
repair problem.
See Chart C.5.
Isolate open
and repair or
adjust VPP as
required.
Repair inverter
circuit consisting
of VR207 and
Q204.
Chart C.4 Bootstrap Fail
October 28, 2002
Host C
Synopsis
Bootstrap Failure.
The host C bootstrap mode is
used during reprogramming of
the host C and DSP FLASH
ROMs. Refer to appropriate
Verify standard
Theory of Operation section for
bias per table
description of bootstrap
Table 3.
operation. Since the operating
code is downloaded through the
serial bus instead of from the
ROM and is initially executed in
the C internal RAM, this is a
good method of verifying
No
Standard
operation of the C. Basic
bias OK?
failure modes:
1) Necessary supplies,
grounds, system clocks not
present.
Yes
2) Vpp voltage not set to
correct voltage for bootstrap
Verify voltage at VR207
mode select or FLASH
(OPTB+/BOOT_SEL/VPP)
programming.
is: 10VDC†VPP†12.7VDC.
3) Improper configuration of
mode select pins.
4) Improper operation of RESET
to the host C.
5) Improper
configuration/operation of the
No
VPP is
host C serial bus.
correct?
Note: This
Yes
configuration
indicates the
Verify MODA and MODB of
C is in
U204 are pulled to a logic
Bootstrap
low state (< .8VDC).
mode waiting
With the host C out of
for data.
reset and prior to any
downloading through the
serial bus:
Verify U204-PD1
No
MODA and
Yes
(BOOT_DATA_OUT) is logic
low and U204-PD0 is logic
MODB are
high (BOOT_DATA_IN).
correct?
Verify
BOOT_DATA_IN and
No
PD0 and PD1
BOOT_DATA_OUT
are correct?
are isolated by
MUX U208.
Yes
1
2
2
1
Initiate download
Verify MUX
and verify the
No
Yes
control on Pin
Signals are
data on
4 of U208 is
BOOT_DATA_IN is
isolated?
low.
echoed out on
BOOT_DATA_OUT
.
Control
Yes
voltage
No
Replace U208.
of BOOT_DATA_IN
Data echoed?
correct?
No
Yes
Repair inverter
circuit
Verify U204 ECLK
composed of
is 1.8432 MHZ
VR207 and
–200ppM.
Q203.
No
Replace Y201.
ECLK frequency
correct?
Yes
Verify download
baud rate is 7200.
No
Baud rate
Yes
Fix baud rate.
correct?
Troubleshooting Charts
Verify continuity
from J201-15 to
U204-PD0.
No
Isolate and
Signal good?
repair open.
Yes
In some
circumstances
additional code is
downloaded and
placed in external
RAM. In this
case, a failure of
the external RAM
could look like a
bootstrap failure.
Replace U204.
MAEPF-24420-A
6881076C25-D
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Table of Contents
Troubleshooting
