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Appendix A. E
2
Key™ Function
The ROCKY-538TXV provides an outstanding E
2
KEY™ function for system
integrator. Based on the E
2
KEY™ you are free to store ID Code, Pass Word, or
Critical Data in the 1Kbit EEPROM. As the EEPROM is nonvolatile memory, you
don’t have to worry about losing 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 need to use E
2
KEY™ you should find the utility inside of the package.
The software utility will include the following four files,
README.DOC
E2KEY.OBJ
EKEYDEMO.C
EKEYDEMO.EXE.
The E2KEY.OBJ provides two library function for user to integrate their application
with E
2
KEY™ function. These library (read_e2key and write_e2key) are
written and compiled in C format. Please refer to the following statement and you
will know how to implement it.
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 address. The address
range is from 0 to 63. The data value is from 0 to 0xffff. */
A quick and easy way to learn to use the function is to first review EKEYDEMO.C
code included.
Please note the E
2
KEY™ function is only available if the parallel port is working. In
other words, you should enable ROCKY-538TXV’s parallel port, otherwise will this
function will be not working.
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