412
Fault Finding of Control Head
TM9100 Service Manual
© Tait Electronics Limited
August 2005
14.9
Function, Scroll, or Selection Keys Faulty
The eight keys of the main keypad (function, scroll, and selection keys) are
connected to the FPGA by an array of three columns and three rows.
During idle operation, the
KEY ROW
signals are driven low by the FPGA and
the
KEY COL
signals (pulled high by an external resistor) are monitored for
activity by the FPGA. A key-press will generate a high-to-low transition on
the associated column
KEY COL
signal. This, in turn, will initiate a sequence
of high output levels on the
KEY ROW
signals to identify which key was
pressed.
The signal at the column side of the switch should be 3.3V. The row side of
the switch should be GND. A successful press will cause transition on
associated KEY_COL signal to low.
Note
CCTM command 1009 can be used to monitor keypad press and
release events.
One Key Faulty
If an individual key is faulty:
1.
Use isopropyl alcohol and a soft lens-cleaning cloth to clean the pad
of the tact switch.
2.
Visually inspect both tact switches (A and B) of a key for short-
circuits. Repair if necessary.
Figure 14.11 Circuit diagram of the function, scroll, and selection keys
KEY COL1
KEY COL2
KEY COL3
3V3
D604
D604
3V3
D620
D620
3V3
D602
D602
S601A
1
2
S601B
1
2
S602A
1
2
S602B
1
2
3V3
3V3
R620
R621
S603A
1
2
S603B
1
2
3V3
R622
Right Selection Key
F3 Key
F4 Key
R623
KEY ROW1
R624
R625
KEY ROW2
KEY ROW3
S604A
1
2
S604B
1
2
S605A
1
2
S605B
1
2
S606A
1
2
S606B
1
2
Scroll-Down Key
Left Selection Key
Scroll-Up Key
S607A
1
2
S607B
1
2
S608A
1
2
S608B
1
2
F1 Key
F2 Key
FPGA
Summary of Contents for TM9100
Page 1: ...TM9100 mobiles Service Manual MMA 00017 01 Issue 1 August 2005 ...
Page 4: ...4 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 10: ...10 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 22: ...22 Introduction TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 62: ...62 Description TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 96: ...96 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 138: ...138 Disassembly and Reassembly TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 152: ...152 Servicing Procedures TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 168: ...168 Interface Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 244: ...244 Receiver Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 396: ...396 CODEC and Audio Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 420: ...420 Fault Finding of Control Head TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 426: ...426 Spare Parts TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 430: ...430 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 444: ...444 TMAA04 05 Ignition Sense Kit TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 448: ...448 TMAA10 01 Desktop Microphone TM9100 Service Manual Tait Electronics Limited August 2005 ...