Data Sheet

ZOE-M8 - Data Sheet
UBX-16008094 - R07 Production Information Functional description
Page 13 of 29
1.19 Safe Boot Mode
If Pin C4 (SAFEBOOT_N) is set to logical “0” at startup, the ZOE-M8 receiver enters Safe Boot Mode. In this mode,
the receiver does not calculate positioning data, but is in a defined state that allows such actions as programming
the flash memory in production, or recovering a corrupted flash memory.
For more information about Safe Boot Mode, see the ZOE-M8 Hardware Integration Manual [1].
1.20 System reset
The ZOE-M8 SiPs provide a RESET_N pin to reset the system and Real-Time Clock (RTC). The RESET_N pin should
be only used in critical situations to recover the system.
1.21 Clock generation
1.21.1 Oscillator
Both ZOE-M8 SiP variants have a TCXO. The TCXO allows accelerated weak signal acquisition, enabling faster start
and reacquisition times.
1.21.2 Real-Time Clock (RTC)
The use of the RTC Clock may be optionally used to maintain time in the event of power failure at VCC. The RTC
is required for hot start, warm start, AssistNow Autonomous, AssistNow Offline and some Power Save Mode
operations.
The use of the RTC is optional. The time information can be generated in one of these ways:
• by connecting to an external RTC crystal (for lower battery current – default mode)
• by sharing from another RTC oscillator used within the application (for lowest system costs and smallest size)
If the main supply voltage fails and a battery is connected to V_BCKP, parts of the baseband section switch off,
but the RTC still runs, providing a timing reference for the receiver. This operating mode is called Hardware Backup
Mode, which enables all relevant data to be saved in the backup RAM to later allow a hot or warm start.
See Table 12 for details of RTC voltage requirements when using an optional RTC.
For more information about crystal operation and configuration, see the ZOE-M8 Hardware Integration
Manual [1].
If neither backup RAM nor RTC are used, the backup battery is not needed and V_BCKP should be connected
to VCC.
1.22 Power management
u-blox ZOE-M8 SiPs offer a power-optimized architecture with built-in autonomous power saving functions to
minimize power consumption at any given time. Furthermore, the receiver can be used in two operating modes:
Continuous mode for best performance or Power Save Mode for optimized power consumption.
1.22.1 DC/DC converter (optional and only on ZOE-M8Q)
ZOE-M8Q has an option to make use of a high-efficient, built-in DC/DC converter to allow low power
consumption. To use the DC/DC converter, a capacitor and an inductor must be added to connect VCC to
V_CORE.
If the built-in DC/DC converter is not used, VCC and V_CORE need to be shorted.
For more information, see the ZOE-M8 Hardware Integration Manual [1].
1.22.2 Operating modes