I've built a serial port connected AVR based device that supports configurable baudrates.
Now, if some software screws up and mess up the baudrate to some unknown rate, there's pretty much no way of contacting the AVR device again w/o resetting the power.
Another thing is that sometimes I've noticed that the device doesn't reset properly during powerup.. Guess the +5V line from the PC powersupply is noisy at powerup... Right now my AVR reset line is just tied to VCC with a resistor, no fancy reset circuit.
Now, I've done some minor research and noticed that modems seems to support reset by pulling the DTR signal.
It looks to me like replacing the pullup resistor with a 5V zenerdiode between the AVR reset pin and VCC, and adding a resistor between the AVR reset pin and the DTR line should solve my problems.
I do have a MAX202 (same thing as max232) on board with one spare reciever line, but since the max202 inverts the signal from active low to active high I can't use it w/o adding a extra inverter.
Does this sound like the ideal solution to the problem, or are there any better alternatives? Guess i just want comments and suggestions for even better alternatives.