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Make sure that the SAFEBOOT_N pin is available for entering Safe Boot Mode. Programming the SQI Flash
memory with a Flash firmware is done typically at production. For this purpose the EVA-M8M modules
have to enter the Safe Boot Mode. More information about SAFEBOOT_N pin see section 2.6.
When the EVA-M8M-1 variant is attached with an external SQI flash without running a Flash firmware,
the default concurrent reception of GPS/QZSS/SBAS and BeiDou remains unchanged. In case the Flash is
also used for execution of firmware update, the default reception will be reset to GPS/QZSS/SBAS and
GLONASS. EVA-M8M-1 can be changed back to concurrent GPS/QZSS/SBAS and BeiDou by sending a
dedicated UBX message (UBX-CFG-GNSS) to the module. More information see the u-blox M8 Receiver
Description Including Protocol Specification [2].
2.3
I/O Pins
All I/O pins make use of internal pull-ups. Thus, there is no need to connect unused pins to VCC_IO.
2.3.1 Time pulse
A configurable time pulse signal is available and configured by default to 1 pulse per second. For further
information see the u-blox M8 Receiver Description Including Protocol Specification [2].
2.3.2 External interrupt
EXTINT is an external interrupt pin with fixed input voltage thresholds with respect to VCC_IO (see the
EVA-M8M Data Sheet [1] for more information). It can be used for wake-up functions in Power Save Mode on all
u-blox M8 modules and for aiding. Leave open if unused; its function is disabled by default. By default the
external interrupt is disabled.
For further information see the u-blox M8 Receiver Description Including Protocol Specification [2].
If the EXTINT is configured for on/off switching of the EVA-M8M series, the internal pull-up becomes
disabled. Thus make sure the EXTINT input is always driven within the defined voltage level by the host.
2.3.3 Active antenna supervisor
EVA-M8M modules support active antenna supervisors. The antenna supervisor gives information about the
status of the active antenna and will turn off the supply to the active antenna in case a short is detected or to
optimize the power consumption when in Power Save Mode.
There is either a 2-pin or a 3-pin antenna supervisor. By default the 2-pin antenna supervisor is enabled.
2.3.3.1
2-pin antenna supervisor
The 2-pin antenna supervisor function, which is enabled by default, consists of the ANT_OK input and the
ANT_OFF output pins.
Function
I/O
Description
ANT_OK
I
Antenna OK
"high" = Antenna OK
"low" = Antenna not OK
ANT_OFF
O
Control signal to turn on and off the antenna supply
"high" = Antenna OFF
"low" = Antenna ON
Table 3: 2-pin antenna supervisor pins
The circuitry, as shown in Appendix A.7 (see Figure 19) provides antenna supply short circuit detection. It will
prevent antenna operation via transistor T1 if a short circuit has been detected or if it is not required (e.g. in
Power Save Mode).
The status of the active antenna can be checked by the UBX-MON-HW message. More information see the
u-blox M8 Receiver Description Including Protocol Specification [2].
UBX-14006179 - R02
Early Production Information
EVA-M8M - Hardware Integration Manual
Remarks
Default configuration
Default configuration
Design-in
Page 13 of 45
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