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AsteRx-i OEM GNSS Module
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2.5
I/O Connectors
The main connector is the 30-pin connector. That connector must always be connected.
The 60-pin connector provides additional signals (IO enable, serial CTS/RTS lines, GPIOs,
Ethernet, 10-MHz reference input, etc). That connector can be ignored and left
unconnected if these signals are not needed.
Warnings
•
All ground pins must be connected (not applicable to the 60-pin connector if that
connector is not used).
•
Do not drive a non-zero voltage into input pins (pins type
“
I
”
in the tables below)
when the receiver is not powered or is in standby (see section 2.8), and during the
first 300 ms after these states. The IO_EN pin of the 60-pin connector indicates
when the board is ready to accept input, and can be used to enable the drivers
driving the input pins. Designs not using the 60-pin connector must either keep
the input pins in hi-Z mode for at least 300 ms after applying power, or drive the
nRST pin low for at least 300 ms after applying power. When not using the IO_EN
pin, it is recommended not to put the board in standby mode.
•
When pull-up/down resistors are needed, use 10 k
.
•
Unused or reserved pins should be left unconnected unless explicitly mentioned
otherwise.
•
In applications where the antenna is located close to the GNSS module, it is good
practice to route all high-speed digital signals (e.g. the SD card signals) in inner
layers of the host PCB, with ground copper at top and bottom layers. This is to
prevent interference into the GNSS signals.
Conventions
•
Pin Type: I=Input, O=Output, P=Power, Ctrl=Control, Clk=Reference clock
•
LVTTL=3V3 Low Voltage TTL: VI
L
≤ 0.8V, V
I
H
≥ 2.0V, VO
L
≤ 0.4V, VO
H
≥ 2.4V.
•
PU: internally pulled up
•
PD: internally pulled down
•
K: keeper input type
60 pin
30 pin
