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4.3.1 Active antenna input
The active antenna input provides 3.3 V supply for active antenna. There is a current limiter circuitry which limits
the maximum current to about 50 mA. Beside the current limiter there is also a current detector circuit which has
the threshold at 5 mA. That is how the RF switch (U14) is set if the active antenna Input goes to ZOE-M8B or the
Simulator input.
Only if current drawn at active antenna input is more than 5 mA, it can be used.
4.3.1.1
Direct ZOE-M8B GNSS performance
There is also an option to have the active antenna input available without connecting an active antenna. In that
case jumper J8 has to be populated, see Figure 2 and Figure 3. Having jumper J8 populated ensures a current draw
at active antenna input and thus the RF switch will still stay at the active antenna input.
Thus a passive antenna or simulator can be connected and performance can be verified when there is no external
LNA in front of ZOE-M8B SiP.
There is DC at the active antenna input, so consider to use a DC block.
4.3.1 Simulator input
At Simulator input there is an external LNA (U12) used in front of ZOE-M8B to show optimal GNSS performance.
This allows verifying datasheet values of ZOE-M8B SiP with a GNSS simulator.
Only if NO current is drawn at the active antenna input (< 5 mA), can the simulator input be used. Ensure
no active antenna is connected to the active antenna input and that Jumper J8 is not populated.
4.4 Digital Connector
There is a 20-pin connector on EVK-M8BZOE. It provides several PIO's, interfaces and supply options. All these pins
are ESD protected.
PIN Nr.
PIN NAME
1
V_BCKP
2
V5_IN
3
NC
4
GND
5
SAFEBOOT_N
6
GND
7
SDA / SPI CS_N
8
GND
9
SCL / SPI SCK
10
GND
11
TIMEPULSE1
12
GND
13
EXTINT0
14
GND
15
RESET_N
16
GND
17
TXD / SPI MISO
18
GND
19
RXD / SPI MOSI
20
GND
Table 5: Connector pin description for EVK-M8BZOE
UBX-17053592 - R03
I/O
LEVEL
I
2.5V...3.6V
Backup supply
I
4.5V...5.5V
Main Supply
-
GND
I
1.8 V
-
GND
I/O
1.8V
DDC SDA or SPI CS_N, depends on interface switch
-
GND
I/O
1.8V
DDC SCL or SPI SCK, depends on interface switch
-
GND
O
1.8V
Timepulse not supported by ZOE-M8B firmware.
-
GND
I
1.8V
External input, can be used for time aiding.
-
GND
I
1.8V
RESET input
-
GND
O
1.8 V
UART TX or SPI MISO, depends on interface switch
-
GND
I
1.8 V
UART RX or SPI MOSI, depends on interface switch
-
-
GND
Early Production Information
EVK-M8BZOE User Guide
DESCRIPTION
Device description
Page 14 of 33
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