EXTENDED EEPROM

The TDS9092 comes with a 256-byte EEPROM as standard. This can be extended by use of any of these devices, which plug into the 8-pin socket in place of the standard PCF8582 256-byte EEPROM. A non-volatile memory connected to the I²C bus of the TDS9092 can be used for these purposes. Unlike a RAM no back-up battery is needed and the stored data is safer from corruption:

q       Data logging of up to 64k bytes (2 chips of 32k bytes can be attached to a TDS9092.

q       Storage of text and menus; can be changed separately from program.

The devices available are:

q       X24C16: 2K byte I²C EEPROM. To fit the device remove the PCF8582 8-pin DIL from its socket and insert the new chip, but bend up pin 7 so that it does not go in the socket. Define these words to access the EEPROM, the address can be from 0 to 2047 ($7FF in hex):

   DECIMAL

   : EEC!  ( byte, address --   store data to EEPROM

          (                     address given

     DUP 256 / $50 + I2C! DROP ;

   : EEC@  ( address -- byte   fetch data from EEPROM

          (                     address given

    DUP 256 / $50 + I2C@ DROP ;

q       24C65: 8K byte I²C EEPROM. To fit the device remove the PCF8582 8-pin DIL from its socket and insert the new chip. The library file _24C65.TDS contains the driver words for byte and word transfer, and for defining the non-volatile variables.

q       24WC256: 32K byte I²C Flash memory. To fit the device remove the PCF8582 8-pin DIL from its socket and insert the new chip. The library file _24C256.TDS contains the driver words for byte and word transfer. Up to 2 chips can be attached to a TDS9092, including one in the 8-pin socket on the computer, The chip can be written byte by byte or sectors of 64 bytes for faster writes. Data retention is quoted by the manufacturer as 100 years minimum and the endurance as 100,000 cycles per byte.