interfacing to a uno

is it possible to use a serial port to alter the running program on the uno?

I am trying to capture a graph of the position of a stepper motor and use this as a basis to change the instructions to motor.

tia david

The arduino cannot re-program itself (write new instructions to it's flash ram) but you could use serial data to alter variables stored in RAM or EEPROM that are used in the servo calculations. RAM variables would need to be re-written every time the arduino is re-powered but you could store the parameters in EEPROM and these won't be lost when the arduino is re-powered.

thanks 4 the info. will try to do what you suggest!!

rgds david