Flash and EEPROM Memory
The EM2001 has three kinds of non-volatile memory onboard:
- 1MB program flash. TiOS occupies 256KB in the program flash memory. The remaining 768KB can be used to store your compiled application binary and permanent (unchangeable) data.
- 1MB flash disk that houses hardened, fault-tolerant file system. The entire disk can be used by your application to store necessary data. The disk is under the control of the flash disk (fd.) object.
- 2KB EEPROM. The EEPROM is almost fully available to your application, save for a small 28-byte area called the "special configuration area". The EEPROM is accessed through the storage (stor.) object.
For more information on fd. and stor. objects 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 EM2000 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 Life.
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.