STM32 is USB Certified on www.usb.org !

[16-32micros]

Posted on December 08, 2007 at 11:42

STM32 is USB Certified on www.usb.org !

#usb-resistor #1.5k-pull-up

[16-32micros]

Posted on May 17, 2011 at 12:17

Dear all,

We are pleased to annouce you that STM32, has already passed the USB-IF Test Procedure for Basic Full Speed products in Bus Powered Configuration, and Now is posted on the USB-IF Integrators List. Product Name: STM32 Product Test ID: 40000455 Go to :

http://www.usb.org/kcompliance/view

-> enter ''STM32'' on the search Enjoy your USB Peripherals designs with STM32, without the need to certify again your Microcontroller. It is already done for you ;) for Free. You need just to certify your end-user Peripherals. For more details refer to

http://www.usb.org/developers/compliance/peripheral_low/

Regards, STOne-32 [ This message was edited by: STOne-32 on 07-11-2007 18:28 ]

[16-32micros]

Posted on May 17, 2011 at 12:17

Here the direct Link :

http://www.usb.org/kcompliance/view/view_item?item_key=070b85f68fb811ecce5d0f993d1ddf1eb43508b9&referring_url=/kshowcase

, If you are a USB-IF member you can also download the checklists and the Results. STOne-32. ;)

[gkpublic]

Posted on March 15, 2013 at 20:15

As a new member, I hope you will be forgiving and helpful!

I am working on the design of a board, captive within a larger system, that uses STM32L152VBT6. We do not need USB certification. Incidental to looking for information on any necessity for DP/DM termination resistances (and values), I found a note in the datasheet: ''

2. To be compliant with the USB 2.0 full speed electrical specification, the USB_DP (D+) pin should be pulled up with a 1.5 kΩ resistor to a 3.0-to-3.6 V voltage range.

'' (

at

http://www.st.com/web/en/resource/technical/document/datasheet/CD00277537.pdf

§6.3.15, under Table 51)

Of the schematics of ST’s reference designs for STM32L-family processors, only “STM32L-DISCOVERY�? implements this. Neither “STM32L152-EVAL�? nor “STM32L152D-EVAL�? nor “STM32L152-SK/IAR�? does.

I stated my opinion on it: ''

it’s pretty clear that satisfactory performance can be obtained while ignoring this

'' (and we have hundreds of deployed boards working adequately) but that statement was excitedly converted to ''

finding a significant design error that should be corrected.

'' I would appreciate others' (especially ST App Engineers!) opinions on the necessity of incorporating this resistor (and any appurtaining other components) into the design. I will separately query about the necessity of DP/DM resistances and the utility of common-mode chokes. Thanks, George

[tsuneo]

Posted on March 16, 2013 at 18:22

STM32L family has on-chip pull-up resistor for USB D+ line.

But because of this silicon bug, an external pull-up is recommended. STM32L15xx Errata http://www.st.com/st-web-ui/static/active/en/resource/technical/document/errata_sheet/CD00278726.pdf 2.5.1 Pull-up resistor has a value lower than 1.5 kOhm The pull-up resistor on USB line is requested to have a nominal value of 1.5 k whereas the characterization of the internal pull-up shows a value between 0.81 k and 0.95 k on the full temperature range. Workaround An external pull-up resistor controlled by a GPIO can be used. common-mode choke Usually, common-mode choke isn't required, unless your USB device would run under heavy noise environment, like close to a high-power motor in a factory. TVS diodes for D+/D- line - recommended https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=%2Fpublic%2FSTe2ecommunities%2Fmcu%2FLists%2Fcortex_mx_stm32%2FSTML152%20EXTI9_5%20and%20USB Tsuneo

[gkpublic]

Posted on March 19, 2013 at 18:00 Tsuneo, Hey, thanks: that clears it up. 'Weird that I don't find mention of the integrated ID resistor in the datasheet. I'm actually dealing with updating a design rather than starting from scratch, and some of what I've inherited is pretty mysterious. The CM choke was probably included ''JIC,'' but though our motor-ridden system is somewhat noisy, there don't appear to be noise problems with the other USB boards' communications, so I would be happy to replace that EOL part with resistors. But what value? The reference designs have 0, 10 or 22Ω, and the datasheet doesn't give any help as far as what is optimal (CYPRESS does for THEIR chips!). We are pushing it a little with loong USB cables to an IPC, so there is incentive to optimize. But it's due-diligence to go get the fast scope anyway.... Thanks, George Editing to provide a reference to another discussion where this is better-addressed:

/f1c3f20d