V1.2 – May-11
User’s Manual
Page 30 of 37
10 Applications and Hints
10.1 Initial Module Start
After initially applying power to the module, it is necessary to start the internal
firmware by toggling the ON_OFF pin. Toggling is done by pulling the signal to HIGH
for about 100ms. This first toggling can be done after a LOW – HIGH transmission
was detected at the WAKEUP pin or by simply waiting for 1s after power-up. In case
of configuration for UART mode, messages should be transmitted afterwards. If no
messages should appear, a new toggling should be applied.
10.2 Proper Shutdown
The A2100-A/B modules require an orderly shutdown process to properly stop
internal operation and complete any writes of critical data to BBRAM or Flash
memory data area. Abrupt removal or droop of main power while the system is
running has risks ranging from minor impact on TTFF to fatal, permanent corruption
of flash memory code area on the module.
A controlled and orderly shutdown while the A2100-A/B is running in full power mode
can be initiated by
•
A 100ms pulse on the ON_OFF pin, or
•
According messages either in NMEA or OSP mode.
The shutdown is completed after maximum 1s. Therefore the module should be
supplied with voltage for that time after the shutdown sequence was initiated.
10.3 SiRFaware
TM
Support
SiRFaware
TM
is a low-power operating mode that seeks to maintain low uncertainty
in position, time, and frequency, and to maintain valid current Ephemeris using either
data collected from satellites in view or Extended Ephemeris methods.
The SiRFaware
TM
mode is entered using the One Socket Protocol, an extension of
the SiRF Binary Protocol. Please refer to the appropriate manual. In order to request
a fix and to exit SiRFaware
TM
it is necessary to toggle the ON_OFF pin. Toggling is
done by pulling the signal to HIGH for about 100ms.
10.4 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
