Garmin APOLLO GX SERIES, Service Manual

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Garmin AT Rev --
© 2004 Garmin AT GX Service Manual 6-3
Resistor jumpers are used on the board to make the appropriate connections for either one or two
parts. The resistors are installed as listed in the following table.
SRAM Configuration Jumpers
SRAMs Configuration R101 R102 R103 R104
1 128K x 8 X X
2 128K x 16 X X
X – indicates installed 0 ohm resistor jumpers
EEPROM
The GX unit uses a non-volatile EEPROM device to store data, such as pilot name, address, phone
number, aircraft ID information, password and the GX unit serial number. Additionally, the EEPROM
stores configuration information such as +5 V calibration data, CDI and VDI calibration data.
The NAV board includes one 16 KBIT (2K x 8) parallel EEPROM, Atmel part no. AT28C16E. The
board layout also accepts an 8 K x 8 EEPROM, an AT26C64. The EEPROM is an 8-bit memory and
cannot be configured as a 16-bit memory.
Read access can be made from the EEPROM as a standard memory device. Write access can also
be made as a standard memory device, but note that there is a minimum period of 200 µsec between
writes. This period is for the internally timed programming cycle. During the programming cycle,
completion status can be read back from the device.
For more information on the EEPROM, refer to the Atmel Nonvolatile Memory Data Book.
PCMCIA Data Card Interface
All GX models utilize a Flybrary database stored on a standard plug-in PCMCIA FLASH memory card
for easy updating and replacement. Simply plug in the new datacard to update your existing database
or change to a new database.
Avionics Outputs
CDI/VDI Outputs
The GX50/60/65 units provide outputs to drive CDI and HSI indicators and an autopilot. These
outputs are to be connected as appropriate for the particular installation. The CDI/HSI outputs may be
connected to a dedicated CDI or HSI or to a shared indicator using an appropriate switching relay.
Flag Outputs
The GX units provide TO/OFF/FROM flag outputs.
Annunciator Outputs
The GX55 provides MSG (message) and PTK (parallel track) annunciator outputs. In addition to
these two outputs, the GX50/60/65 units provide OBS/HLD (waypoint sequencing hold), APPRCH
(approach) and ACTIVE (approach active) annunciator outputs.
Altitude Input
The GX50/60/65 includes an altitude input, which is used for GPS RAIM calculations as well as
providing for altitude assist functions such as altitude preset and hold and 3D airspace alerts. The