Hi,

I'm new to PIC. I am planning to implement a control system using PIC16F877.
I'll be using a keypad, LCD, almost all I/O pins (to input the control
variables, operate four switches, PWM etc.).

The code for all this is going to be large, no doubt. A PIC expert could
optimise it to fit in the 8K ROM of the PIC, but as I'm a novice I'm not
sure I'll be able to do so. In any case, since I'll either use JAL or a
C-compiler, the code will be more than 8K. So now my question is:

Can we interface an EEPROM [specifically: 24LC256, 32Kbyte Flash EEPROM
(I2C)] to the PIC in such a way that the firmware code can be written in the
EEPROM, from where the PIC can fetch it in packets and run it?

It doesn't matter to my application if the effective operating speed
decreases, because I'll be controlling pH, temperature, dissolved oxygen
(all these take few minutes to adjust).

If no, and the firmware is greater than 8K, then what should I do? Is there
anything available with Microchip that has a larger (flash) ROM and as many
I/O as the PIC 16F877? I've read about PIC18F242, but it still isn't out in
the market.

Peace,
Mohit Mahajan.


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