Author Topic: EEVblog #357 - USB Supply Power-up Testing  (Read 39077 times)

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Offline EEVblog

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #25 on: September 22, 2012, 09:44:51 am »
The FT232RL is almost zero external parts count and a reasonably small package.

$2.65 in 2000qty from Digikey.
FT232XS is only $1.58
Also 16pin SSOP vs 28pin SSOP

Maybe cheaper on the gray market of course, but dunno.

Like I said, it was cheaper and smaller, so I went with the 230XS.

Dave.
 

Offline klinkerstein

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #26 on: September 22, 2012, 10:11:16 am »
The FT232RL is almost zero external parts count and a reasonably small package.

$2.65 in 2000qty from Digikey.
FT232XS is only $1.58
Also 16pin SSOP vs 28pin SSOP

Maybe cheaper on the gray market of course, but dunno.

Like I said, it was cheaper and smaller, so I went with the 230XS.

Dave.

On the other hand, the FT232RL is almost industry standard ;-)
 

Offline EEVblog

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #27 on: September 22, 2012, 10:47:18 am »
On the other hand, the FT232RL is almost industry standard ;-)

Yeah, it seemed like a good idea at the time  ::)

Dave.
 

Offline David_AVD

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #28 on: September 22, 2012, 10:49:18 am »
$2.65 in 2000qty from Digikey.
FT232XS is only $1.58

I'd pay $1 more just to use a more universal product.  I do understand the tough choices when it comes down to choosing parts though.
 

Offline EEVblog

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #29 on: September 22, 2012, 10:54:16 am »
I'd pay $1 more just to use a more universal product.  I do understand the tough choices when it comes down to choosing parts though.

That $1 more would make it the most expensive device on the board, and a larger increase on the retail price in which the BOM cost was creeping away beyond what I wanted.
And there is the extra size too which played into it.

Dave.
 

Offline David_AVD

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #30 on: September 22, 2012, 10:56:26 am »
That $1 more would make it the most expensive device on the board, and a larger increase on the retail price in which the BOM cost was creeping away beyond what I wanted.

Ah, ya penny pinching bugger.  lmao!
 

Offline pachuma

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #31 on: September 22, 2012, 11:09:31 am »
So, why don't you get rid of the FTDI USB to UART converter altogether and knock off a few dollars worth of useless logic?

Simply change the AVR to a micro-controller with a native USB interface either from Microchip or Atmel. Its something I've used on endless projects and helps to reduce the cost substantially.

As we say over here: "if you want to get rid of rabies, simply kill the dog", i.e. solve the problem by removing it.
 

Offline David_AVD

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #32 on: September 22, 2012, 11:11:31 am »
The one great thing about using the FTDI devices is the driver support.  That's something that never seems to be as easy with USB enabled micros.
 

Offline EEVblog

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #33 on: September 22, 2012, 12:25:36 pm »
So, why don't you get rid of the FTDI USB to UART converter altogether and knock off a few dollars worth of useless logic?

It needs to be isolated!

Dave.
 

Offline firewalker

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #34 on: September 22, 2012, 12:36:31 pm »
What about Prolific chips (PL2303)? I believe the cost less.

Alexander.
Become a realist, stay a dreamer.

 

Offline dolabra

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #35 on: September 22, 2012, 12:46:33 pm »
So, why don't you get rid of the FTDI USB to UART converter altogether and knock off a few dollars worth of useless logic?

Simply change the AVR to a micro-controller with a native USB interface either from Microchip or Atmel. Its something I've used on endless projects and helps to reduce the cost substantially.

As we say over here: "if you want to get rid of rabies, simply kill the dog", i.e. solve the problem by removing it.

Do you sell these projects?  How do you handle USB Vendor and device ID?
 

Offline OndraSter

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #36 on: September 22, 2012, 01:01:01 pm »
Also, why are you using FTDI? There are AVRs and PICs with USB built-in.

There needs to be electrical isolation. Doing so with USB is generally not cheap.

Dave.

I see. You are optically isolating the UART interface. Neat!

(I couldn't find the "new" rev schematics on the web? Or is it the revC?)
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Offline pachuma

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #37 on: September 22, 2012, 01:02:31 pm »
If you use Atmel´s chips you can use their VID/PID for your device.
You will not be able to splodge the USB compliant logo, but heck, it very much depends what you what to do with it.
http://support.atmel.com/bin/customer.exe?=&action=viewKbEntry&id=220
Ofcourse, there are several alternatives.
 

Offline firewalker

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #38 on: September 22, 2012, 01:03:50 pm »
Do you sell these projects?  How do you handle USB Vendor and device ID?

There is a way to use Atmel's, Microchip's PID:VID if I remember correctly?

Using Arduino's USB<->UART code and PID:VID for a consumer product is legal?

Alexander.
Become a realist, stay a dreamer.

 

Offline pachuma

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #39 on: September 22, 2012, 01:19:53 pm »
So, why don't you get rid of the FTDI USB to UART converter altogether and knock off a few dollars worth of useless logic?

It needs to be isolated!

Dave.
OK, IC.

I was not aware that you had that requirement on spec, I need to go through the whole thread :)
Then you have little choice. Unless when working off the battery it will be but not while in charge or configuration.

BTW, have you considered to add a SCPI parser to control the gadget?
 

Offline gxti

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #40 on: September 22, 2012, 02:32:12 pm »
The one great thing about using the FTDI devices is the driver support.  That's something that never seems to be as easy with USB enabled micros.
The unfortunate thing about FTDI chips is that they need drivers at all. "Class-compliant" implementations, including MCP2200 but also probably all vendor-supplied USB UART examples, don't need a driver. Unfortunately due to the way windows does USB you still need a .inf file to bind the VID/PID to windows' class driver but on linux/mac it's plug-and-play.
 

Offline Baliszoft

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #41 on: September 22, 2012, 04:07:21 pm »
Quote
There is a way to use Atmel's, Microchip's PID:VID if I remember correctly?

Using Arduino's USB<->UART code and PID:VID for a consumer product is legal?


I got my "own" PID from Microchip in 1 or 2 days after requesting. As far as i remember a maximum of 10k units can be sold with this. Of course you also have to use a microchip product with this PID:VID combo.
 

Offline Baliszoft

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #42 on: September 22, 2012, 04:11:15 pm »
The one great thing about using the FTDI devices is the driver support.  That's something that never seems to be as easy with USB enabled micros.

Right. Even the firmware is a PITA, not mentioning the pc drivers. LibUsb is a good (and free) alternative, however. Works well.
 

Offline Rutger

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #43 on: September 22, 2012, 04:22:19 pm »
I don't understand why Dave does use a bigger battery power supply for the main power with more power options, get ride of the isolation and only allow the USB for charging the battery. Add an option for an externally isolated power supply and you have successfully merged both power supplies into 1 small one.

Oh and while were are at it, get ride of most buttons and display and only allow the interface via Bluetooth with an app for iphones & android.
« Last Edit: September 22, 2012, 04:25:09 pm by Rutger »
 

Offline Bored@Work

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #44 on: September 22, 2012, 05:16:28 pm »
Oh and while were are at it, get ride of most buttons and display and only allow the interface via Bluetooth with an app for iphones & android.

That is just wank. You have never worked on a bench, doing some real work, did you? Then you would know you need knobs, real knobs, not that stupid fondling junk to wank about.
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Offline dolabra

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #45 on: September 22, 2012, 05:59:19 pm »
Using Arduino's USB<->UART code and PID:VID for a consumer product is legal?

I do not believe that it is.

HW vendors like microchip and atmel have some special deal with the USB forum, everyone else has a non-transferable license to use the IDs
 

Offline dolabra

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #46 on: September 22, 2012, 06:13:44 pm »
If you use Atmel´s chips you can use their VID/PID for your device.
You will not be able to splodge the USB compliant logo, but heck, it very much depends what you what to do with it.
http://support.atmel.com/bin/customer.exe?=&action=viewKbEntry&id=220
Ofcourse, there are several alternatives.

from the link: "Customer must integrate the Atmel USB Flash Microcontroller Software and the USB descriptors with no changes"
The way I read this is that you can use their example code unmodified. Which seem useless unless you just want a CDC class device to attach to something else.
 

Offline T4P

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #47 on: September 22, 2012, 07:52:54 pm »
What about Prolific chips (PL2303)? I believe the cost less.

Alexander.
I can't see a way to get them in one-off quantities (well, unless you bought a OHL rs232 adaptor and hack out the chip) for prototyping
That is just wank. You have never worked on a bench, doing some real work, did you? Then you would know you need knobs, real knobs, not that stupid fondling junk to wank about.
Indeed. I hate wirelessly controlled devices
I don't understand why Dave does use a bigger battery power supply for the main power with more power options, get ride of the isolation and only allow the USB for charging the battery. Add an option for an externally isolated power supply and you have successfully merged both power supplies into 1 small one.
Yeah, really? He wanted a ISOLATED power supply that is totally isolated from the USB because of the noise that USB can coexist on the ground cable
So what if your battery is dead? Get a new battery? Don't want to! I don't want to have to wait for the battery to arrive from somewhere just because it's not easy to find locally at least cheap
 

Offline Baliszoft

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #48 on: September 22, 2012, 08:23:57 pm »
http://ww1.microchip.com/downloads/en/DeviceDoc/APPLICATION%20FOR%20SUBLICENSE%20TO%20USB%20VID%20v3%20UPDATED.pdf

Quote from: APPLICATION FOR SUBLICENSE TO
MICROCHIP UNIVERSAL SERIAL BUS VENDOR ID
Microchip’s VID and the assigned PID may be used: (a) for internal development purposes; and (b) during initial production which shall not exceed 10,000 units of your product. Once production exceeds the limit of 10,000 units, then the Sublicense shall automatically terminate (unless terminated earlier) and you will be responsible for obtaining a Vendor ID number from USB-IF, Inc.

If Atmel does not allow to do this, that is a big FAIL *oaaaaaa*
« Last Edit: September 22, 2012, 08:26:24 pm by Baliszoft »
 

Offline pachuma

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #49 on: September 22, 2012, 08:46:42 pm »
Oh and while were are at it, get ride of most buttons and display and only allow the interface via Bluetooth with an app for iphones & android.

That is just wank. You have never worked on a bench, doing some real work, did you? Then you would know you need knobs, real knobs, not that stupid fondling junk to wank about.
+1
 


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