STM32F205RCTb USB OTG FS :Is Pull up required on DP

jagbir · ‎2015-01-25

Posted on January 25, 2015 at 18:13

We are using USB FS ( PA11 / PA12 ) in device mode. We have grounded ID pin i.e. PA 10 .We have not used any Pull up or pull down on DP and DM pin as described in eval board schematics STM32 20-21-45-46 G-EVAL USB_OTG_FS .

We received our actual application board with STM32F205RCTb, till now we were using Evaluation Board(STM3220G-EVAL).

We used USB Device sample example(stm32cubef2) in FS mode on Eval Board, it worked fine. IDE used is IAR

In our fabricated boards :

When boot loader is there i.e without any firmware loaded board in Host PC. Now we are trying to port the eval kit code into our actual board(STM32F205RCTb), however the board is not detected as device in PC(Host).

We modified target controller(STM32F205RC) and preprocessor(STM32F205XX) in project settings.

Is there any external Pull up required on DP to detect the board as device in PC.

Tesla DeLorean · ‎2015-01-25

Posted on January 25, 2015 at 21:24

So are you pulling BOOT0 high so it goes into the System Loader?

Do you have a connection to USART1/USART3 so you can confirm chip functionality via the System Loader?

Can you download code via JTAG/SWD?

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jagbir · ‎2015-01-25

Posted on January 26, 2015 at 05:32

Clive.

We have both options to pulll up and pull down BOOT 0.

1.By default we are pulled up BOOT 0 and that is the reason I think the host PC detects my board as DFU bootloader.

2.We can program the board through 20 pin JTAG successfully .

3.We are using UART2 and UART 6

3.As we have to work in user flash so we have realized that BOOT0 needs to be pulled down

4.After the BOOT0 pull down we can control the GPIOs LED and UART 6 is working.

5.we have used USB Device sample example(stm32cubef2) in FS mode on Eval Board

Now our device is not being detected by the Host PC if we connect it through a microUSB cable but the board was being detected in bootloader mode.

Some folks are saying that a 1.5K pull is required on DP line but ths pull up is not there in Eval board schematics.

Need urgent help.