This is the interface that I built:

Techedge ALDL

I was also looking at the MAX232 interface on Craig Moates page, just out of curiosity sake what is the major difference between these 2 interfaces?? I one I can see right off the bat is the techedge is powered via laptop serial port and the other requires a +12VDC power source. Does one work better or faster than the other?? Sorry but I am not an electronics wizard, just know how to follow directions and solder.

Also on the techedge page it says this:

We also avoid using a separate power supply by powering the MAX chip from the PC's serial port (DTR and RTS signals must be set to +ve).

What is +ve, and how do you set DTR & RTS signals to that???

THanks

 

Anyone??

 

Yeah, that's the case. What you say is true. There are a couple articles around which describe in detail how to set those values to "+12v" or "+5v", I forget, but it can be done.

Just build the one with the external power supply. I'll post another schematic soon which is somewhat more robust and includes provisions for either power supply option.

 

Has anyone ever really looked at the current drive from a generic PC UART to see if it will source enough current for powering the MAX232? I would do what Craid said and use an external supply. A 9V battery works nice and will last forever at the current rating required.
J