FTDI FT232RL USB UART interface

[GartnerProspect]

I'm not sure if you're regarding the self-powering or the USB device ID.

The ID wouldn't be used for initial setup, it would be used to link a particular peice of hardware to a particular configuration on the PC. The ID is there by default, so it's only requirement is to use the interface chip.

Self powering however would merely be a convenience for bench testing in the short term, haven't really figured any use long term... Though I've been there enough to realize that removing the ECU for testing is more common than anybody would like to admit.

[Fred]

No, no, the ID will just be that of the generic UART to USB adapter. most likely. They contain an eeprom chip on them that you may be able to reprogram if you wanted to. Our EMS won't have it's own ID, it will just be a device on a serial line. The ID will be that of the usb chip that does the conversion and will cause windoze or Linux to load the correct driver for it at the time.

[GartnerProspect]

The FTDI chip is programmed with a unique serial ID per chip, for every chip they manufacture.

It also has a generic ID of course for the USB driver.

here is a snippet

FTDIChip-IDâ„¢ - Each FT232R is assigned a unique number which is burnt into the device at manufacture. This ID number cannot be reprogrammed by product manufacturers or end-users. This allows the possibility of using FT232R based dongles for software licensing.

It also has built in EEPROM for USB VID and PID. You can get a block of free Product IDs through FTDI.

So the device is pretty flexible.

[jharvey]

Has anybody used one of these or a variation there-of?
Post up what you know, from what I've seen this is one of the more popular and availible solutions. And the drivers are royalty free, basic COM, so shouldn't change anything on the software side for use on megasquirt.

Personally I'm not a fan of the FTDI chips. I'm not saying they are bad, but they do limit your design. I prefer the EZUSB chips from cypress. They offer the same features as the FTDI chip low cost, royalty free, basic COM, ect, so they are the same in that regard. The difference is that EZUSB is a boot strapped 8051. When you plug it in, there is no firmware in the USB device. You have to upload the firmware and tell the device what it's going to be. This means you can change it from a serial port, to some other kind of port with ease. Here's a project that use the EZUSB FX2 http://gnuradio.org/trac.

You can find a USB serial adapter and hack it for a quick prototype. Here are some instructions on how to do this

http://www.hhhh.org/wiml/proj/keyspan.html

Or you can find a supplier of a pre-made board like this one.

http://www.elrasoft.com/hsusbm.htm

[Fred]

Welcome along Jared :-)

Fred.

[jbelanger]

I'm not familiar with the EZUSB (had a quick look at the provided links and the datasheet) but the main issue I see is that this is a 3.3V device. And I think that if other I/Os are needed (which is not a priority at this time I think), there other ways to get them that may be more effective.

Jean

[jharvey]

Thanks for the welcome Fred.

About the EZUSB, I'm not certain if it's 3.3 or other. Usually these types of chips have multiple voltage capabilities, purchased by altering the part number. I haven't looked into it. I know it's usually powered by the USB port, so I would have assumed it's 5v. 3.3v has it's bonuses if you can use it. The higher the voltage, the harder you have to drive a signal to get data across. Running at 3.3v allows for higher capacitance on the driving lines. Allowed higher capacitance means a higher frequency on the low pass filter that is your data line.

I also didn't want to muddy the water to much, but PSoC's USB (also by cypress) is very similar to EZUSB. I know a PSoC is 5v compatible, and has many other functions. But I'll try not to comment to much about that here.