User's Manual

GSM/GPRS/GNSS Module Series
MC60 Hardware Design
MC60_Hardware_Design Confidential / Released 38 / 99
3.4.2.3. Backup Mode
Backup mode requires lower power consumption than standby mode. In this mode, the GNSS part stops
acquiring and tracking satellites, but the backed-up memory in backup domain which contains all the
necessary GNSS information for quick start-up and a small amount of user configuration variables is alive.
Due to the backed-up memory, EASY technology is available. The current consumption in this mode is
about 14uA.
The following methods will make GNSS part enter into backup mode:
 Sending PMTK command “$PMTK225,4*2F” will make GNSS part enter into backup mode.
 Cutting off GNSS_VCC and keeping VRTC powered will make GNSS part enter into back mode from
full on mode.
The following method will make GNSS part exit from backup mode:
 As long as the GNSS_VCC is powered, the GNSS part will exit from backup mode and enter full on
mode immediately.
1. In all-in-one solution, all PMTK commands used for the GNSS part should be sent through GSM
UART when the GSM part is in Normal Mode or Minimum Functionality Mode and when the GNSS
part is powered on. Make sure the GSM UART Port is accessible.
2. In all-in-one solution, if the GSM part is in sleep mode, it is recommended to set the GNSS part to
backup mode to save power. This is because the GSM UART Port does not work in sleep mode, and
due to this, customers cannot obtain the location information through GSM UART Port even if the
GNSS part works in normal mode.
3. In stand-alone solution, all PMTK commands used for the GNSS part can be sent through GNSS
UART in any mode of GSM part.
3.4.3. Summary of GSM and GNSS Parts’ State in All-in-one Solution
Table 11: Combination States of GSM and GNSS Parts in All-in-one Solution
GSM Part Modes GNSS Part Modes
Full on Standby Backup
Normal
  
Sleep

Minimum Functionality
  
NOTES