80
Embedded Modules
© Tibbo Technology Inc.
The EEPROM is almost fully available to your application, save for a small 28-byte
area called "special configuration area". The EEPROM is accessed through the stor.
object (see TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual). Details on the special
configuration area are provided in the Platform-dependent Programming Information
section inside the EM500 platform documentation (same manual).
On the advice of one of our customers we are giving you the following
reminder: Like all other EEPROMs on the market, EEPROM ICs used in Tibbo
devices allow for a limited number of write cycles. As the Wikipedia article on
EEPROMs (
https://en.wikipedia.org/wiki/EEPROM
) states, the EEPROM "
...has a
limited life for erasing and reprogramming, now reaching a million operations in
modern EEPROMs. In an EEPROM that is frequently reprogrammed while the
computer is in use, the life of the EEPROM is an important design consideration.
"
When planning to use the stor. object, please carefully consider if the planned mode
of EEPROM use will allow the EEPROM to work reliably through the entire projected
life of your product. For more information see
Prolonging and Estimating EEPROM
Like all other flash memory devices on the market, flash ICs used in Tibbo products
only allow for a limited number of write cycles. As the Wikipedia article on flash
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.
4.5.1.4
LED Lines
The EM500 has three LED control lines -- SG, SR, SE. All lines have the same
internal structure and the LEDs should be connected as shown on the schematic
diagram below. The maximum load for each line is 10mA. For a small LED, a 330 Ohm
series resistor will provide sufficient brightness.