10.7 Push-to-Fix Mode
Push-to-Fix mode is designed for the application that requires infrequent position
reporting. The receiver generally stays in a low-power mode, up to 2 hours, but
wakes up periodically to refresh position, time, ephemeris data and RTC calibration.
The push-to-fix mode is initialized and entered using the SiRF Binary Protocol.
Please refer to the appropriate manual, paying particular attention to the paragraph
titled “Set TricklePower Parameters”. In order to request a fix outside the specified
duty cycles, it is necessary to toggle the pin ON_OFF. Toggling is done by pulling
the signal to HIGH for about 100ms.
For more information see “GPS AppNote Firmware GSC3”.
10.8 Hibernate Mode
The two ways as described within this paragraph to send a module into Hibernate
Mode should be implemented in order to avoid loss of data which might in rare
cases lead to a cold start of the module.
10.8.1 Entering Hibernate Mode with ON_OFF Pin
From firmware version 3.2.5, firmware support for ON_OFF has been included,
hence, a rising pulse on the ON_OFF pin will put the A1084 GPS receiver into hi-
bernate state if it is on and wake it up if it is in sleep state. During sleep state the
receiver draws 20 µA typically and maintains RTC and SRAM. Here Vcc must not
be switched off. See also “
Error! Reference source not found.
”. Therefore this
method can be used for configurations where no additional Vbak is available.
10.8.2 Entering Hibernate Mode with Shutdown Command
When a separate Vbak supply is foreseen, an alternative method to enter Hibernate
Mode is by sending a shutdown command. From firmware version 3.5.0 onwards
this is possible using the command
$PSRF117,16*0B
In NMEA mode as described in the manual “GPS Firmware GSC3 3.5.0”. In SiRF
Binary mode the according command can be found in the “SiRF Binary Reference
Manual” – Software Commanded Off – Message ID 205. After a delay of about 2 s
or after the signal RFPWUP went LOW Vcc can be disconnected. The RTC will
keep on running and SRAM is backed with the typical current of 20 µA drawn from
Vbak. See also “Figure 6: Minimum configuration A1035-H with Vbak”.
V1.5 – Dec-09
User’s Manual
Page 33 of 37
