TMS320F28377D: USB Bulk Transfer Raw ADC Data

Mark Siefring

Part Number: TMS320F28377D
Other Parts Discussed in Thread: C2000WARE

Hi, I am trying to send raw ADC data over USB to be viewed on my PC. I currently have my ADC sampling at 100KHz and I am using the DMA to move my results into Ram. I want to use the usb_dev_bulk example provided in C2000ware in order to send my data. I am successfully able to print messages into a terminal with this example, and I have modified the example for continuous sampling and DMA transfer. My issue is writing my data to the USB Tx buffer. Is it possible to do a direct write to the buffer and use the USBBufferDataWritten function to send the raw ADC data to the PC? Any support would be greatly appreciated.

Thanks,

Mark

over 8 years ago

0 Mark Siefring over 8 years ago

Prodigy 115 points

Sorry, I meant to say using the USBBufferWrite function.

0 Sal Pezzino over 8 years ago in reply to Mark Siefring

TI__Mastermind 32995 points

This is possible, but the internal structures of the USB must be maintained/updated.

It is possible, but there are other things in the library that need to updated. Look at the scheduleNextTranmission function. this may help.

Unfortunately, we do not have a trimmed down USBlib example for this.

sal

0 Sal Pezzino over 8 years ago in reply to Sal Pezzino

TI__Mastermind 32995 points

I recommend using the full USBlibrary first to understand exactly what is being done internal to the library, and then begin to cut out things you don't need or think you can do more efficiently.

sal

0 Mark Siefring over 8 years ago in reply to Sal Pezzino

Prodigy 115 points

Hi Sal,

I'm not sure if I necessarily have to send raw data. I am a student and am new to programming these controllers. Would you recommend a bulk transfer or a different method for transferring ADC data in relatively Real-Time? I can output to terminal if that's the best option, or I can try other methods, I just need to be able to log the ADC data.

Thanks,

Mark

0 Sal Pezzino over 8 years ago in reply to Mark Siefring

TI__Mastermind 32995 points

You can use the SCI to print to a terminal. This may be fast enough for you.

Please see the SCI examples and USB examples in C2000Ware for reference and a place to start.

sal

0 Mark Siefring over 8 years ago in reply to Sal Pezzino

Prodigy 115 points

Hi Sal,

If I use SCI to print to a terminal, wouldn't I need an extremely high baud rate? Somewhere in the multiple Megabaud? Is the SCI able to handle this?

Mark

0 Sal Pezzino over 8 years ago in reply to Mark Siefring

TI__Mastermind 32995 points

Why would you need it? Are you saying you would require such a high bit rate because you have so much data to send?

sal

0 Mark Siefring over 8 years ago in reply to Sal Pezzino

Prodigy 115 points

If I am understanding correctly, each ADC sample is 16 bits of data. At a sampling rate of 100KHz, that seems like a lot of data to print to a terminal accurately.

Mark

0 Mark Siefring over 8 years ago in reply to Mark Siefring

Prodigy 115 points

Hi Sal,

How do I adjust the baud rate in the USB_Dev_Bulk example provided by TI?

0 Sal Pezzino over 8 years ago in reply to Mark Siefring

TI__Mastermind 32995 points

The baud rate is only valid for the SCI communication. The USB is acting as a CDC, but it does not use a baud rate, it uses the USB protocol and is full speed.

sal

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28377D: USB Bulk Transfer Raw ADC Data