I finished these off last night, and I must say, I'm very impressed with the reliability of the Max232 based connection; it is on par with the FTDI/USB connection on my Diecimila board and the iDuino (and every other FT232 based board). Gone is the questionable reliability of the transistor-based connection.
The boards are based off the Freeduino PTH layout and include all the usual Diecimila-style goodies like auto-reset and a (optional) 3.3V regulated output. Obviously the layout is compatible with shields.
You may have better luck than me, but I couldn't fit the MAX232 and associated bits into the footprint of even the much larger SS-Serial board. Even double sided the board still has a few vias.
If you can fit it onto a reasonably sized single sided board, I'd love to hear, otherwise, I sell just the bare board for exactly this reason. If you'd like a starting point, the board/schematic are available at the end of the directions.
Your directions are very detailed, thanks! Do you know a cheap source for the MAX232 or equivalent? The RoHS compliant replacement for it is called MAX232CPE+ but costs ~ £25 here in the UK...
Your directions are very detailed, thanks! Do you know a cheap source for the MAX232 or equivalent? The RoHS compliant replacement for it is called MAX232CPE+ but costs ~ £25 here in the UK...
Your directions are very detailed, thanks! Do you know a cheap source for the MAX232 or equivalent? The RoHS compliant replacement for it is called MAX232CPE+ but costs ~ £25 here in the UK...
If your ordering a serial board anyway (or even if your not), I carry MAX232 clones (DS14C232CN) for 90¢ (about £0.45).
I am sorry ,but I didn`t understand why all grounded point leaved without any ground connection,should I add a ground plane to the board.
I maked freeduino v 1.2 and after that I noticed that grounded points has not any ground connection ,so I redesigned it,but want to know what was the designer porpuse to leave all grounded points lonely.
I see it is marked 5V and 9V . I dont have eagle to look Is this able to feed 9V into jumper marked so and is this put back through 5V reg first? How does power in work that way?
The "9V" pin is connected to the cathode of the power input protection diode. So it's not exactly the same as connecting to the power jack, but you can use it to feed unregulated power to the 5V regulator input.
So it does feed to the 5Vregulator then . It is not feed 9V to the chip?
It can be used two ways. If there is an extenal voltage source plugged into the external power connector, then the Vin pin can output that same external voltage (minus one diode voltage drop) and be used to power things that require the higher voltage avalible from an external power source, there is a 1 amp limit based on the series voltage polarity protection diode.
If there is nothing plugged into the external power connector then the Vin pin can be used to input a voltage that only goes to the input of the on board +5vdc voltage regulator.
I am sorry ,but I didn`t understand why all grounded point leaved without any ground connection,should I add a ground plane to the board.
I maked freeduino v 1.2 and after that I noticed that grounded points has not any ground connection ,so I redesigned it,but want to know what was the designer porpuse to leave all grounded points lonely.