PORTS Forum

Ports and Interfaces => USB => Topic started by: april on April 12, 2013, 01:09:26 am

Title: Problem with signal on D+ D- line?
Post by: april on April 12, 2013, 01:09:26 am: Hi,

First I'm sorry about my English. ;)
I'm developing usb host 1.1 on the board that is designed by myself.
At this time, I always detect when the mitsumi keyboard is plugged into the host, however, for as genius keypad, I often can not because interrupt is not generated by host.
According to USB made simple - part 3, I try read signal on D+, D- line and I explored that the keypad falls into Single Ended One (SE1) state:
D+ = high, D- = high, this is the illegal condition where both lines are high.

I don't know why, anybody can help me.

Thanks very much.
Title: Re: Problem with signal on D+ D- line?
Post by: Jan Axelson on April 12, 2013, 11:12:08 am: What hardware are you using for the host?

Are you using a provided OS or other firmware provided by a hardware vendor or other source?
Title: Re: Problem with signal on D+ D- line?
Post by: Barry Twycross on April 12, 2013, 01:30:37 pm: Do you have the proper pull downs on your host?
Title: Re: Problem with signal on D+ D- line?
Post by: april on April 16, 2013, 06:36:45 am: Quote from: Jan Axelson on April 12, 2013, 11:12:08 am
What hardware are you using for the host?

Are you using a provided OS or other firmware provided by a hardware vendor or other source?

Hi Jan,

I'm using STM32F407VG MCU from STMicroelectronics for the host and building my firmware base on the example that is provided by hardware vendor.

My error status:
Power on -> Plug keyboard into host -> always detect keyboard successfully.
Plug keyboard into host -> Power on -> SE1 (sometimes successfully).

I'm thinking the usb power supply gets problem..
Title: Re: Problem with signal on D+ D- line?
Post by: april on April 16, 2013, 06:42:12 am: Quote from: Barry Twycross on April 12, 2013, 01:30:37 pm
Do you have the proper pull downs on your host?

Thank Barry, but I'm sure I had the pull down on both lines (D- = 0, D+ = 0) at usb host core initialization.
Title: Re: Problem with signal on D+ D- line?
Post by: Tsuneo on April 18, 2013, 11:15:30 am: Hi april,

Quote
I'm using STM32F407VG MCU from STMicroelectronics for the host and building my firmware base on the example that is provided by hardware vendor.
What is your dev board, STM32F4-Discovery?
And are you working on STM32_USB-Host-Device_Lib_V2.1.0 library?
http://www.st.com/web/catalog/tools/FM147/CL1794/SC961/SS1743/PF257882

Tsuneo
Title: Re: Problem with signal on D+ D- line?
Post by: april on May 10, 2013, 06:22:55 am: Quote from: Tsuneo on April 18, 2013, 11:15:30 am
Hi april,

Quote
I'm using STM32F407VG MCU from STMicroelectronics for the host and building my firmware base on the example that is provided by hardware vendor.
What is your dev board, STM32F4-Discovery?
And are you working on STM32_USB-Host-Device_Lib_V2.1.0 library?
http://www.st.com/web/catalog/tools/FM147/CL1794/SC961/SS1743/PF257882

Tsuneo

Hi Tsuneo, sorry for a long delay, I have just finished this usb project :D

No, I'm not use STM32F4-Discovery board, just use STM32F407VG MCU from ST in my own board.
And I'm working on STM32_USB-Host-Device_Lib_V2.1.0 library. Are you trying this library?

As I mentioned above, that's true about problem on usb power supply, after replacing the new one, my board works well.

Thank everyone for helping.