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Boards
© Tibbo Technology Inc.
memory (
https://en.wikipedia.org/wiki/Flash_memory
) explains, modern flash ICs still
suffer from comparatively low write endurance. In Tibbo devices, this endurance is
around 100'000 write cycles per sector. When you are using the flash memory for
file storage, the fd. object employs sector wear leveling to maximize the life of the
flash IC (but the life still remains limited). If your application employs direct sector
access, then it is your job to plan the application around the life limitations of the
flash memory. For data that changes often, consider using the EEPROM memory
instead. EEPROMs have much better endurance.
5.2.1.7
Real-time Counter and Backup Supercap
The real-time counter (RTC) of the EM1001 is a free-running 40-bit register that
increments at a rate of 128Hz.
As a source of backup power, the EM1001 relies on a supercapacitor. Only EM1001-
S devices carry this supercapacitor (see
Specifications and Ordering Info
).
The supercapacitor has many advantages -- it charges instantly and has a virtually
unlimited lifespan. The disadvantage is that the supercapacitor is only able to
sustain the RTC for several days (about 6 days for the 4F supercapacitor of the
EM1001-S), which may appear insufficient. Remember, however, that the EM1001 is
usually connected to the network and can always synchronize its clock* with an
Internet time server or a master clock on the main server of your system.
Therefore, the role of the supercapacitor is to provide the backup power during
relatively short periods of power interruption, i.e. when the device is unplugged and
moved to another location, or when the device is powered off over the weekend.
Your Tibbo BASIC/C application can access the RTC through the RTC (rtc.) object,
which is documented in the TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual.
*With the right application, that is.
5.2.1.8
LEDs and LED Lines
The EM1001 has three LEDs onboard:
·
The red and green status LEDs.
·
The yellow Ethernet status LED.
Further information on status LEDs can be found in
The EM1001 also has two control lines -- SG and SR -- for connecting to external
green and red status LEDs. These external LEDs work in parallel with the onboard
LEDs. Since the maximum sink current of an I/O line is 10mA and the onboard LEDs
already consume around 7mA, externally connected LEDs must not consume over
3mA of current. Connect external SR and SG LEDS through buffers (logic gates) if
higher current is desired. SG and SR lines are active low, i.e. an LEDs must turn on
when its control line is at LOW. Take this into consideration when designing the LED
circuit.
Your Tibbo BASIC/C application can control red and green status LEDs, as well as up
to four externally connected LED pairs through the pattern (pat.) object, which is
documented in the TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual.