Author Topic: USB-UART bridge chip recommendations?  (Read 5099 times)

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Offline Dave92F1

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USB-UART bridge chip recommendations?
« on: October 16, 2015, 03:10:04 am »
I want to pick a USB-UART bridge IC for a microcontroller project (MCU will talk UART; USB to a PC).

There seem to be hundreds of different bridge chips out there. I know FTDI is the popular one, but I'm looking for:

* Small footprint (internal oscillators, minimal additional parts)
* Support of 460,800 baud
* Simple

Nice but not critical:

* Support of hardware flow control (RTS/CTS)
* Support of USB-C connector (well, it would be nice; maybe too early for that)

Cost is not a big issue (it's a hobby project, so I won't be buying a lot of these).

Any suggestions?

(Is there some web site that has a good index of what parts are available, to help narrow it down? Looking at distributor sites, they don't seem to list all the above details in their catalogs - you have to read each datasheet one by one.)
 

Offline westfw

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Re: USB-UART bridge chip recommendations?
« Reply #1 on: October 16, 2015, 04:50:35 pm »
Is there a good reason that you don't want to use one of the existing (and very inexpensive) modules?  A lot of them have similar or identical pinouts, so you can experiment and make sure there is a hardware/driver combo that you like.

IMO, the FTDIs are still good products, if you're careful to get non-counterfeits.   Various people are mad at the company, for their "driver bricks counterfeit chips" driver.  Their newer chips (FT230X/FT231X) are smaller and cheaper.  AND there are official, tiny, modules...

CP2102 and Prolific are common choices as well, but the "counterfeit" landscape is confusing.  ch340g is a newer Chinese Chip a a relatively friendly package (SOIC), but it needs an external crystal, and I don't know if you can find a "real" vendor.

Microchip has a chip that is actually a pre-programmed PIC microcontroller, and so is potentially "fixable." (also needs a crystal.  But newer PIC microcontrollers don't.  Go figure.)
 

Offline lod

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Re: USB-UART bridge chip recommendations?
« Reply #2 on: October 17, 2015, 12:51:02 am »
Something you should consider, especially if you are distributing these at all is OS support.

Different devices offer different solutions to Windows driver support, much nicer if an external driver isn't required.
They all tend to come up as a generic device on Linux and friends, so better support there.

I have also had difficult in the past pushing high baud rate (1MB was definitely a problem) data down a Windows terminal device, not sure if it is still an issue.


USB-C is just a new plug which wraps a standard USB 2.0 data pair so any USB chip will support it.


Honestly in your position I would just go with the latest FTDI chip.
They are popular and ubiquitous for a reason, you don't have any special requirements they don't meet, they are easy to get, well understood and easy to get support.
 

Offline nctnico

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Re: USB-UART bridge chip recommendations?
« Reply #3 on: October 17, 2015, 01:00:15 am »
In my experience the CP210x chips are more stable in a noisy environment. I can reproduce the difference in reliability on my workbench so this is definitely not hear-say. My chip-of-choice is definitely the CP210x even though it is slightly harder to solder.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline stevenhoneyman

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Re: USB-UART bridge chip recommendations?
« Reply #4 on: October 17, 2015, 02:21:18 am »
FT230X: easy-to-solder for beginners, and driver support & compatibility
CP2102/CP2104: smaller physical size, and much lower cost
 

Offline blueskull

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Re: USB-UART bridge chip recommendations?
« Reply #5 on: October 17, 2015, 02:49:29 am »
CP2104+1, works fine for me.

4*4mm footprint, all integrated except for ESD diodes, up to 2Mbaud/s, hardware flow control.
 

Offline Dave92F1

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Re: USB-UART bridge chip recommendations?
« Reply #6 on: October 18, 2015, 03:02:47 am »
Thanks for all the answers!

Soldering small-pitch SMD is no problem for me.

Does the CP210x require a special driver on Windows, or does it work out-of-the box?

Any opinions on the Microchip MCP2221? It seems to have an internal osc, and is small (as small as 4x4 mm in a QFN).
 

Offline blueskull

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Re: USB-UART bridge chip recommendations?
« Reply #7 on: October 18, 2015, 03:19:51 am »
Thanks for all the answers!

Soldering small-pitch SMD is no problem for me.

Does the CP210x require a special driver on Windows, or does it work out-of-the box?

Any opinions on the Microchip MCP2221? It seems to have an internal osc, and is small (as small as 4x4 mm in a QFN).

Both have internal osc. Not sure if the CP2104 driver is in Windows out of the box, but it is definitely in Windows Update.

On recent Mac OSX, at least 10.6 and modern Linux distributions the driver is supplied within kernels.

CP2104 is also 4 by 4 mm.
 

Online Jeroen3

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Re: USB-UART bridge chip recommendations?
« Reply #8 on: October 18, 2015, 11:22:56 pm »
If you do not want a driver, get the UART-HID bridge from Silabs.
 

Offline hamdi.tn

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Re: USB-UART bridge chip recommendations?
« Reply #9 on: October 23, 2015, 04:19:08 am »
most mcu now have embedded usb controller, an code available for usb to uart bridge ( at least what i saw with microchip and st) i think you can choose any one of those chip that meet your need and build one on your own.
But none of them support USB with internal crystal.

so if you are not limited by your mcu choice for this project , i think it will be good to pick one with usb and you don't need any bridge.
 

Online Gyro

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Re: USB-UART bridge chip recommendations?
« Reply #10 on: October 23, 2015, 05:14:46 am »
You might want to check out this thread, it was started at the height of the FTDI driver bricking episode and compares the strengths and weaknesses of probably every USB-Serial solution known to mankind.  :)

http://www.eevblog.com/forum/reviews/alternatives-to-ftdi-usb-to-uart-converter/
« Last Edit: October 23, 2015, 05:22:34 am by Gyro »
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Offline andersm

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Re: USB-UART bridge chip recommendations?
« Reply #11 on: October 23, 2015, 05:18:49 am »
most mcu now have embedded usb controller, an code available for usb to uart bridge ( at least what i saw with microchip and st) i think you can choose any one of those chip that meet your need and build one on your own.
But none of them support USB with internal crystal.
There are MCUs that do USB without a crystal, eg. Atmel's SAM D11 or ST's STM32L052.

Offline hamdi.tn

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Re: USB-UART bridge chip recommendations?
« Reply #12 on: October 23, 2015, 05:45:21 am »
most mcu now have embedded usb controller, an code available for usb to uart bridge ( at least what i saw with microchip and st) i think you can choose any one of those chip that meet your need and build one on your own.
But none of them support USB with internal crystal.
There are MCUs that do USB without a crystal, eg. Atmel's SAM D11 or ST's STM32L052.

my mistake, i was talking about the ones i worked with or saw their DS.
 

Offline JTR

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Re: USB-UART bridge chip recommendations?
« Reply #13 on: October 24, 2015, 12:49:44 pm »
most mcu now have embedded usb controller, an code available for usb to uart bridge ( at least what i saw with microchip and st) i think you can choose any one of those chip that meet your need and build one on your own.
But none of them support USB with internal crystal.
There are MCUs that do USB without a crystal, eg. Atmel's SAM D11 or ST's STM32L052.

And about a dozen or so PICs also are fully spec'ed to work without a crystal...
 

Offline blueskull

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Re: USB-UART bridge chip recommendations?
« Reply #14 on: October 24, 2015, 03:56:58 pm »
If performance doesn't matter, even vusb on avr can do it.
 

Offline AlxDroidDev

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Re: USB-UART bridge chip recommendations?
« Reply #15 on: October 29, 2015, 12:34:01 pm »
FT230X: easy-to-solder for beginners, and driver support & compatibility
CP2102/CP2104: smaller physical size, and much lower cost

I also vouch for the CP2102.
"The nice thing about standards is that you have so many to choose from." (Andrew S. Tanenbaum)
 

Offline richardman

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Re: USB-UART bridge chip recommendations?
« Reply #16 on: November 03, 2015, 07:57:53 pm »
My own experience with USB-UART CABLE is that the CP and Prolific chip cables do not work on my particular need (a CAN232 dongle) whereas the FTDI-based cable works great. YMMV. Since price is not a consideration, I'd just go with the FTDI
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Offline nctnico

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Re: USB-UART bridge chip recommendations?
« Reply #17 on: November 03, 2015, 11:17:02 pm »
My own experience with USB-UART CABLE is that the CP and Prolific chip cables do not work on my particular need (a CAN232 dongle) whereas the FTDI-based cable works great. YMMV. Since price is not a consideration, I'd just go with the FTDI
There can be differences in timing between the various USB-serial dongles. The fact the creator of the CAN232 software didn't care to test his CAN232 dongle with other USB-serial bridges doesn't make the FTDI ones better! It is just dumb luck. Given the fact you can run into fakes which are then rendered useless by the driver without warning and the FTDI chip is prone to erratic behaviour FTDI isn't even on my list.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 


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