read/write EEPROM on 18F8520

[WizardOfAz]

Although you might want to finish understanding how to manage the ram, program memory, and eeprom, eeprom is probably not the best choice for your sine table. The C compiler allows putting read-only data in program memory. The loader will automatically put your table in program rom, and the compiler will automatically generate the appropriate code to access it there. This would be the easiest way to do your sin table. You wouldn't have to read it in or anything special. Just declare it to be in rom, like this:

unsigned char /* or whatever you want */ rom sinTable[256] = {0, 5, 10, 15, ... more table values...};

The rom keyword will cause this table to be stored in rom rather than ram, the latter being the much more limited resource. Declared this way, you can access it in C just like any other array. Just don't try to store to it.

Now, if you really want to put it in EEPROM, the simplest way would be to declare the table as above, run a for loop to copy the table to EEPROM using writeEE provided by Random Dude in the prior post. Download the program and run it, just once, and the EEPROM will be saved until changed by some other program. After that download a program that accesses the table using readEE.

A more typical use for the EEPROM would be, for example, calibration of a resistive sensor. If for some reason the sensor calibration changes often, you could have code that is always loaded that can run a calibration sequence and store the resulting data in EEPROM, and the normal runtime could access the current calibration from that table.

Have fun.

Bill