STM CircleOS forum / USB OTG connector

mtreese · 2011-05-23 17:15:18

The evoPrimer F107 board claims to have a USB OTG connection yet it has a mini-B connector vs a mini-A connector. Also the ID pin on the connector is not connected on the uC. What this means is that you will have to force the uC to be a host or device initially and use HNP and also that you must use a mini-B connection. If you follow USB standards, since the evoPrimer is the end with the mini-B connection it must come up first as a device and then must negotiate to be a host via the HNP. This means you must connect a device that also supports OTG or cobble together a USB cord and code to make it work.

This only affects you if you are wanting to use the USB OTG in host mode as the way it is designed seems to be only with device mode in mind.

Is there any plans for fixing this by putting a mini-A connection on the board and connecting the ID pin so that one may make full use (correct use) of the advertised OTG capability?

Last edited by mtreese (2011-05-23 17:17:38)

yrt · 2011-05-24 10:10:35

You're right, the ID pin is missing (its a mistake ). You can link it to only available µC pin PB4, or on the extension connector (not simple).
For your information, ST uses Micro A-B connectors on their STM32C EVAL evaluation card, with cord adapters.
http://www.st.com/internet/evalboard/product/217965.jsp

mtreese · 2011-05-24 14:18:37

Thanks for the information and the quick response. I have one of those ST boards but I was hoping that I was going to be able to make use of the evoPrimer form factor. I can switch out the connector to a mini-AB or even a micro-AB and connect the ID pin should I so decide, I just wish the documentation had made this clear before ordering since it clearly states that this board is configured for USB-OTG use. This is true in some respects since the STM32 supports USB-OTG but the board does not support it fully without modification.

johnsmith22 · 2011-07-26 10:32:56

USB OTG cable for C7(c7 box does not contain OTG cable) in the market of Nepal...today I made my own USB OTG adapter my soldering data cable. Now i can enjoy connecting pendrive, memory card, USB harddisk, Mouse and Keyboard. You can also make that...
1) Tear the Micro Usb port(Phone side) of ur data cable(is used CA-101D) with knife.

2) After tearing You will see 5 pins. Among them one is left without connection. That is called ID pin. If you connect id pin with ground(where u c black wire) then ur mobile works as host for usb.

3) When u finish....protect ur soldering with tape.

4) Now assemble the port

5) You are finished....Now If u have (female-female) usb connector then u can connect devices to ur mobile. if u cant find the here is the idea.

6) Purchase multi usb adapter(available in the market) or we can say USB hub, This is the device which can expand one usb port to many.

7) cut two female port from that.

8) Get RJ-45 connectors and connect to the wires using cramping tool.

9) do same for another cable. and connect both using Rj-45 to Rj-45 connector box(it is also easily available).

10) Now ur finished....u can connect ur pendrive

# 1 2011-05-23 17:15:18 USB OTG connector

USB OTG connector

# 2 2011-05-24 10:10:35 USB OTG connector

Re: USB OTG connector

# 3 2011-05-24 14:18:37 USB OTG connector

Re: USB OTG connector

# 4 2011-07-26 10:32:56 USB OTG connector

Re: USB OTG connector

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