Garmin GNC 420 Maintenance Manual page 156

B.3.5 J12
Pin Name
LD1 through LD8
CLK_ROW
CLK_SHIFT
FLM
LCD_OFFN
T1
T2
VCC
LCD_HV
GND
SPARE
BEZEL_TEMP
PB_OUT_A
PB_OUT_B
PB_OUT_C
PB_OUT_D
PB_IN_A
PB_IN_B
PB_IN_C
PB_IN_D
GND
NOT USED
NOT USED
NOT USED
Page B-6
Rev. C
Table B-7. J12 Descriptions
Pin # I/O
46-50 O LOWER half display DATA output.
3-5
6 O Pulse high for typically 310 ns at a period of 33.236 us
(30.088 kHz). This line loads the next row of data in the
display drivers. There are 66 CLK_ROW pulses for each
FLM pulse.
7 O Pulse high for a typical 120 or 180 ns. Pulses come in bursts
of 90 with about 180 ns of low time between each. The
bursts of 90 come at the CLK_ROW frequency. The rising
edge of the first pulse in a burst of 90 is about 1.22 us after
the rising edge of a CLK_ROW pulse.
8 O First Line Marker that pulses high for 33.236 us (30.088
kHz) at period of 2.19359 ms (455.873 Hz). The rising edge
of FLM is about 1.1 us after the rising edge of a CLK_ROW
pulse.
9 O LCD OFF Not is a output that turns off the display if low.
10 I Thermistor 1 input is used to measure LCD temperature.
Resistance of input is 10 k ohm to VCC.
11 I Thermistor 1 input is used to measure heater temperature.
Resistance of input is 2.2 k ohm to VCC.
12 O
13 O LCD contrast voltage.
14 O Ground.
15,
30..37,65
66..70
16 I Bezel temperature is used by the board to measure
temperature.
55 O Push Button Matrix.
20 O
54 O
19 O
53 I
18 I
52 I
17 I
21 O Ground.
22
23
24
Description
400 SERIES MAINTENANCE MANUAL
P/N 190-00140-05