USBD - Universal serial bus device

[alexlöddeköpinge]

Hi everyone,

I'm reading the documentation about USBD and I have some questions about it.

1) What's the EasyDMA? Maybe I understand what it is but I am not sure so I ask.

2) In Figure 9 of the documentation about USBD I see "Populate Data RAM buffer". What does it means? If I want to do a bulk IN transfer I have to write the RAM buffer and then through a easyDMA transfer the data is transfered? If yes, where?

Thanks a lot

BR

[awneil]

alexlöddeköpinge said:

What's the EasyDMA?

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf52832.ps.v1.1%2Feasydma.html

alexlöddeköpinge said:

"Populate Data RAM buffer". What does it means?

"Populate" = fill it with all the required information/data

[alexlöddeköpinge]

So I have to populate the RAM with the required information/data and then data are transfered to USB register throug a easyDMA transfer. Rigth?

When I want to do a bulk IN transation,the data that I want to send from nrf52840 to PC where have to be written? In RAM buffer?

Is there any example of bulk transfer of data from the nRF52840 ADC to PC(host)?

Thanks

[Sigurd]

alexlöddeköpinge said:

So I have to populate the RAM with the required information/data and then data are transfered to USB register throug a easyDMA transfer. Rigth?

 You tell the USB peripheral where in RAM the data is located, with the EPIN.PTR register, then when you start the transfer, the USB peripheral will automatically retrieve the data from RAM location you pointed it to.

alexlöddeköpinge said:

When I want to do a bulk IN transation,the data that I want to send from nrf52840 to PC where have to be written? In RAM buffer?

 Yes, RAM buffer.

alexlöddeköpinge said:

Is there any example of bulk transfer of data from the nRF52840 ADC to PC(host)?

 No, not for ADC data. But I believe the usbd_msc example uses bulk transfer.