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Appendix B. E
2
Key™ Function
The ROCKY-3742EVFG provides an outstanding E
2
KEY™
function for system integrator. Based on the E
2
KEY™, you
can free to store the ID Code, Password or Critical Data in the
1Kbit EEPROM. Because the EEPROM is nonvolatile
memory, you don’t have to worry for losing very important
data.
Basically the E
2
KEY™ is based on a 1Kbit EEPROM which is
configured to 64 words(from 0 to 63). You could access (read
or write) each word at any time.
When you start to use the E
2
KEY™ you should have the
utility in the package. The software utility will include four files
as follows,
README.DOC
E2KEY.OBJ
EKEYDEMO.C
EKEYDEMO.EXE.
The E2KEY.OBJ provides two library functions for user to
integrate their application with E
2
KEY™ function. These
library
(read_e2key and write_e2key)
are written and
compiled in C language. Please check the following statement,
then you will know how to implement it easily.
unsigned int read_e2key(unsigned int address)
/* This function will return the E
2
KEY™’s data at address.
The address range is from 0 to 63. Return data is one word,16
bits
*/
void write_e2key(unsigned int address,unsigned data)
/* This function will write the given data to E
2
KEY™ at certain
address. The address range is from 0 to 63. The data value is
from 0 to 0xffff. */
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To easily start to use the function, please refer to the included
EKEYDEMO.C code at first.
