Drop in USB conversion for V3 boards

[Karl Buchka]

Just put the finishing touches on this single-sided prototype board. It’s a drop-in USB conversion for a V3 PCB:





Installation is pretty straightforward. Simply desolder (or don’t populate) the serial connector, the MAX232 (IC nearest the serial connector), the bootstrap caps, and drop this board in place. Makes for a cleaner and simpler install than the standard USB-UART breakout boards.

It places the connector in the hole normally reserved for the DB9, so no case mods are required.

2.2 and 3.57 variants wouldn't be terribly difficult to make either. Would there be interest in something like this? I couldn't find any vendor specific rules here, so if I'm stepping on someone's toes, please let me know.

[Peter Florance]

Hopefully you are using FTDI chip?

[Karl Buchka]

You mean if I make more of these? Probably. FTDI's USB to UART chips have always served me well. The pictured board is using an FT232RL that I had laying around, but I've been anxious to try one of their new FT230X chips. They're hard to get though.

[Peter Florance]

You mean if I make more of these? Probably. FTDI's USB to UART chips have always served me well. The pictured board is using an FT232RL that I had laying around, but I've been anxious to try one of their new FT230X chips. They're hard to get though.

Agree; the FTDI based converters are way better. Plus it's in the MS3, so there is some compatibility there.

[racingmini_mtl]

I've just had a quick look but is there any advantage for the FT230X other than a smaller package? It seems to be pretty much the exact same thing as the FT232RL. And you might want to consider adding an isolator to completely isolate the MS from the USB port.

Jean

[Karl Buchka]

Some isolation circuitry is probably a good idea. Thanks.

The FT230X is about half the price of an FT232RL. I have used the CP2102 as well for both MS and VEMS, but I would rather pay a bit more for a package that doesn't give me gray hairs.

[racingmini_mtl]

The FT230X is about half the price of an FT232RL.

Yeah, I noticed that after posting but the problem is that it doesn't seem to be available anywhere, not even from FTDI. But when that changes, it will be a good alternative that I'll look into for my own projects.

Jean

[imakehp]

Anything ever finalize with this usb add on? I like the clean "drop in" design.
Are they, or did they ever, become for sale?

[dontz125]

The original poster may have noticed that FTDI has been selling such a thing for years. The DB9-USB-RS232-F is on the shelf at Mouser, US$19.25 each.

[imakehp]

Well I'll be damned....thanks Dontz

[imakehp]

One more thing please....Our MS board would take the "F" correct?

[dontz125]

Correct. I spent a few minutes earlier, pondering the datasheets for the MS and adapter. With the -F model, pin 2 is TX out to the world from the processor, and pin 3 is RX from the world to the chip; this matches the MS pinout.

That, and the MS uses a female DB9 connector ...