Motorola Gm Controller Manual

							Controller Board Audio and Signalling Circuits 1-17
2.5 RECEIVE SIGNALLING CIRCUITS
Refer to Figure 5-6 for reference for the following sections.
Figure 4-2 Receive Signalling Paths
2.5.1 Sub-audible (PL/DPL) and High Speed Data Decoder
The ASFIC CMP (U0221) is used to filter and limit all received data. The data enters the ASFIC CMP 
at input DISC (U0221-2). Inside U0221 the data is filtered according to data type (HS or LS), then it 
is limited to a 0-5V digital level. The MDC and trunking high speed data appear at U0221-19, where 
it connects to the µP U0101-82
The low speed limited data output (PL, DPL, and trunking LS) appears at U0221-18, where it 
connects to the µP U0101-80.
The low speed data is read by the µP at twice the frequency of the sampling waveform; a latch 
configuration in the ASFIC CMP stores one bit every clock cycle. The external capacitors C0236, and 
C0244 set the low frequency pole for a zero crossings detector in the limiters for PL and HS data. 
The hysterisis of these limiters is programmed based on the type of received data.
2.5.2 Alert Tone  Circuits
When the software determines that it needs to give the operator an audible feedback (for a good key 
press, or for a bad key press), or radio status (trunked system busy, phone call, circuit failures), it 
sends an alert tone to the speaker. It does so by sending SPI BUS data to U0221 which sets up the 
audio path to the speaker for alert tones. The alert tone itself can be generated in one of two ways: 
internally by the ASFIC CMP, or externally using the µP and the ASFIC CMP.
The allowable internal alert tones are 304, 608, 911, and 1823Hz. In this case a code contained 
within the SPI BUS load to the ASFIC CMP sets up the path and determines the tone frequency, and 
at what volume level to generate the tone. (It does not have to be related to the voice volume setting).
For external alert tones, the µP can generate any tone within the 100-3000Hz audio band. This is 
accomplished by the µP generating a square wave which enters the ASFIC CMP at U0221-19. 
Inside the ASFIC CMP this signal is routed to the alert tone generator
The output of the generator is summed into the audio chain just after the RX audio de-emphasis 
block. Inside U0221 the tone is amplified and filtered, then passed through the 8-bit digital volume 
attenuator, which is typically loaded with a special value for alert tone audio. The tone exits at U0221-
41 and is routed to the audio PA like receive audio
DET AUDIO
DISCRIMINATOR AUDIO
FROM RF SECTION
(IF  IC)19
18
25
2
82
80
DISC
PLCAP2LSIO HSIO DATA FILTER
AND DEEMPHASISLIMITER
FILTER
LIMITERASFIC_CMP
U0221
MICRO
CONTROLLER
U0101
85 44
8 PLCAP 
						

							1-18THEORY OF OPERATION
2.6 Voice Storage (optional)
The Voice Storage (VS) option can be used to store audio signals coming from the rec\
eiver or from  
the microphone. Any stored audio signal can be played back over the radio’s speaker or sent out via 
the radio’s transmitter. 
The Voice Storage option can by placed on the controller section or on an additional option board  
which resides on option board connector J0551. Voice Storage IC U0301 provides all required 
functionality and is pow ered from 3.3  volts regulator U0351 which  is p ow ered from the regulated 5 
volts. Dual shottky diode D0301 reduces the supply voltage for U0301 to 3 volts. The microprocessor 
controls U0301 via SPI bus lines CLK (U0301-8), DATA (U0301-10) and MISO (U0301-11). To 
transfer data, the µP first selects the U0301 via address decoder U0141, \
line VS CS and U0301 pin 
9. Then the µP sends data through line DATA and receives data through line MISO. Pin 2 (RAC) of 
U0301 indicates the end of a message row by a low state for 12.5 ms and connects to µP pin 52. A 
low at pin 5 (INT), which is connected to µP pin 55 indicates that th\
e Voice Storage IC requires 
service from the µP. 
Audio, either from the radio’s receiver or from one of the microphone inputs, emerges the ASFIC  
CMP (U0221) at pin 39, is buffered by op-amp U0341-1 and enters the Voice Storage IC U0301 at 
pin 25. During playback, the stored audio emerges U0301 at pin 20. To transmit the audio signal it is 
fed through resistive divider R0344 / R0345 and line VS MIC to input selector IC U0251. When this 
path is selected by the µP via ASFIC CMP port GCB 4, the audio signal enters the ASFIC CMP at 
pin 48 and is processed like normal transmit audio. To play the stored audio over the radio’s speaker, 
the audio from U0301 pin 20 is buffered by op-amp U0341-2 and fed via switch U0342 and line FLAT 
RX SND to ASFIC CMP pin 10 (UIO). In this case, this ASFIC CMP pin is programmed as input and 
feeds the audio signal through the normal receiver audio path to the speaker or handset. Switch 
U0342 is controlled by the µP via ASFIC CMP port GCB 4 and feeds the stored audio only to the 
ASFIC CMP port UIO when it is programmed as input. 
						

							Chapter 2
TROUBLESHOOTING CHARTS
1.0 Controller Troubleshooting  Chart 
Controller Check
Power Up 
Alert Tone
 OK?
Speaker & 
Control 
Head OK?
U0101
EXTAL= 
7.3728 MHz/ 
14.7456 
MHz? 
BUS+
activity when 
volume knob 
rotated?
MCU is OK
Not able to 
program 
RF Board ICsBefore replacing 
MCU, check SPI 
clock, SPI data, 
and RF IC select 
Replace 
Speaker / Con-
trol Head
U0221 Pin 34 = 
16.8 MHz?
Check 
FGU
Reprogram the 
correct data. & 
Check ASFIC 
and MCU
Check Control 
Head and MCU 
(U0101, U0121, 
U0122, U0111)
Press PTT. No 
RF Output Pow-
er.
Red LED 
lights up?
Check 
Control 
Head
Check 
FGU & 
Transmitter Audio
at Pin 41 
U0221?
Enable External PTT 
with CPS External PTT en-
abled with CPS?Radio could 
not PTT 
externally
DC
at as-
signed Acc. 
Con. Pin 
DC chang-
es?
Check Components 
between U0221 and 
U0271
Check Con-
nection to uP 
port
PTT
NO
YES
NO
YES
YES YESYES
NO
NO
YES
NO
YES
NO
YESNO
YES EXT
PTT RX
AUDIO
Check 
Accessories J0501
Audio at Pin 
16 & 
Pin 1
Check Spk. 
Flex Connec-
tion & Control 
Audio 
at Audio PA 
(U0271) 
input
Check AS-
FIC U0221
Check
 Audio PA 
(U0271)
Check Re-
ceiver &
 IF ICAudio at 
Pin 2 
U0221?
NO
NO
NO YESYES
NO
YES
NO
Before troubleshooting the controller section ac-
cording to this chart please check the following:
1. Check tuning and CPS settings
2. Check if Alert Tones are enabled
3. Check if Control Head is OK
4. Check board visually9.3V
DC at Pin 5 
of U0641? 
YESNO
5V DC at 
Pin OUT of 
U0651? 
YESNO
Check U0641, Q0641, 
Q0661, D0660 & 
D0661
Check U0651, D0651, 
D0621 
						

							2-2TROUBLESHOOTING CHARTS 
						

							Chapter 3
CONTROLLER SCHEMATICS / PARTS LIST
1.0 Allocation of Schematics and Circuit Boards
1.1 Controller Circuits
This Chapter shows the Schematics and the the Parts Lists for the Controller circuits. 
1.2 Voice Storage Facility
The Voice Storage is fitted on all MPT radios GM640/660/1280 and on GM380 as standard. 
The schematics, component layout and parts list for these circuits are shown in this chapter. 
The Voice Storage schematic is shown in Tables below. 
. Table 3-1   
Controller T2 Diagrams and Parts Lists
Controller T2 used on PCB : 8486172B0 4 VH F, 1-25W
SCHEMATICS
Controller Overall 
Supply Voltage
Audio
I/O
Microprocessor
Page 3-3 
Page 3-4
Page 3-5
Page 3-6
Page 3-7
Parts List Controller T2 Page 3-8
Table 3-2    Controller T5 Diagrams and Parts Lists
Controller T5 used on PCB : 8486172B06  VHF, 1-25W
SCHEMATICS
Controller Overall 
Supply Voltage
Audio
I/O
Microprocessor
Voice Storage (if fitted)
Page 3-10 
Page 3-11
Page 3-12
Page 3-13
Page 3-14
Page 3-15
Parts List Controller T5 Page 3-16 
						

							3-2  Con troller schematics / parts list
.
Table 3-3   Controller T6 Diagrams and Parts Lists
Controller T6/T7 used on PCB : T6 on 8486206B06  LB1, 60W
T6 on  8486140B12  VHF, 25-45W
T6 on  8480643z06  UHF B1, 25-40W
T7 on  8486172B07  VHF, 1-25W
T7 on  8485670z02  UHF B1, 1-25W
SCHEMATICS
Controller Overall 
Supply Voltage
Audio
I/O T6
I/O T7
Microprocessor
Voice Storage (if fitted)
Page 3-19 
Page 3-20
Page 3-21
Page 3-22
Page 3-23
Page 3-24
Page 3-25
Parts List Controller T6/T7 Page 3-26