Motorola V186 - Cell Phone - GSM System Planner Manual page 13

The CPU has a low drift RTC. The date and time are retained using an on-board
rechargeable lithium battery. The CPU date and time can be set using the ACE3600 STS.
The CPU can also be synchronized with other RTUs in the system, using the system
clock.
The CPU's rechargeable lithium battery provides backup power and data retention for the
SRAM and RTC. Typically, the battery will preserve the data stored in the SRAM and
RTC for 60 continuous days without power. When the SRAM option is not used, the
Lithium battery will keep the Real Time Clock (RTC) running for a longer period of
time.
The CPU module also includes:
Buzzer (audio indication), which is used to indicate task completion (such as end
of download/upload, restart etc.) and can also be controlled from the user
application program.
Pushbuttons on the front panel, PB1 and PB2. These pushbuttons are used for
activating and testing the module LEDs, restarting the unit, erasing the user Flash
memory and activating memory test. The pushbuttons can also be monitored by
the user application program (when it is running) for the application purposes.
Status LEDS which indicate the CPU status during startup (boot), run-time or
when there is a failure. Communication LEDs are used to indicate the
communication port status. User LEDs can be used by the user application
program.
The CPU's firmware is a real-time multitasking operating system, based on the Wind
River VxWorks OS. The CPU is shipped from the factory with the most recent firmware
version, and it can be updated/replaced using a remote or local connection. Downloading
firmware updates is performed using the STS. (See Downloading to a Site in the
ACE3600 STS User Guide.) If the new firmware download stops or fails, the CPU will
restart with the existing firmware.
9
CPU Modules