Flash and EEPROM Memory

These are the three types of flash memory that you will encounter on DS/WS110x devices:

  • Unified flash memory – stores the TiOS firmware, compiled Tibbo BASIC/C app, and, optionally, the flash disk. All flash space not occupied by TiOS is available to the compiled Tibbo BASIC/C app. All flash space left over from TiOS and the app can be formatted as a fault-tolerant flash disk. The flash disk is accessible through the fd. object (see the TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual).
  • Program flash memory — stores the TiOS firmware and compiled Tibbo BASIC app(s). All flash space not occupied by TiOS is available to the compiled Tibbo BASIC/C app.
  • Data flash memory — the entire memory space can be formatted as a fault-tolerant flash disk. The flash disk is accessible through the fd. object.

In addition, all DS/WS110x devices are equipped with EEPROM memory. A small area at the bottom of the EEPROM is occupied by the Special Configuration Section (SCS) that stores the device's MAC(s) and password. The rest of the EEPROM is available to Tibbo BASIC/C applications. The EEPROM is accessible through the stor. object (see the TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual).

Device

Unified flash memory

(available app/disk space)

Program flash memory

(available app space)

Data flash memory

EEPROM

(space occupied by the SCS)

DS1100

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512KB

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208 bytes

DS1101

1,024KB (64KB)

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2KB (8 bytes)

DS1102

1,024KB (64KB)

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2KB (8 bytes)

WS1102

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4MB (4,048KB)

4MB (4,048KB)

2KB (28 bytes)

note_warning-wtOn 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 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 explains, modern flash ICs still suffer from comparatively low write endurance. In Tibbo devices, this endurance is about 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 instead — EEPROMs have much better endurance.