Sanguino with a serial port


Has anyone built a Sanguino with MAX232 to connect to COM1 port of a desktop PC?

Can he/she please share the schematic?

I have built one and it is not working.

I am slightly confused whether RTS or DTR line should be used for resetting the chip.


-P W Dandekar

I had one of these development boards from Sparkfun which I put a 644P in and converted it to use the Sanguino bootloader. I just put a header on to connect a FTDI programing cable, and it was then a sanguino with a serial port.

Have a look at the schematic of the board to find out how to do the MAX232 part.

Hope that is of some help


Thanks James,

I looked at the Sparkfun schematic as well as similar board from - AVR-P40-8515.

In both cases, they have converted DTR/RTS signals from RS232 to TTL and left them unconnected on pins. They have not connected RTS/DTR signal to RESET via a 0.1 mfd capacitor as they do in FREEDUINO Serial or SEVERINO.

If you look at the Sanguino schematic by Zack Hoeken, you will see RTS connected to RESET via a 0.1 mfd capacitor. But he uses a FTDI USB to 232 converter chip.

I wanted to try the same here with MAX232.

Thanks again.