TDC7201-ZAX-EVM: Noob to MSP430 (and CCS) seeking advice on USB settings and maximizing throughput/performance.

B Lench

Part Number: TDC7201-ZAX-EVM
Other Parts Discussed in Thread: MSP430F5529, TDC7200EVM, TDC7201, MSP430USBDEVPACK

Hi,

I'm using the TDC7201EVM with the MSP430F5529 LaunchPad. I've compiled the TDC7200EVM_USB example project (using CCS 8.3). It's calling "cdc" USB funnctions.included in "USBConstructs.h".

My project is to make TOF measurements at about 1KHz, That is, every millisecond there will be a Start trigger followed by two stops. The second (final) stop may occur, say, 950us after the corresponding Start. The two stops are independent signals, one Stop on each TDC. After the second stop, the TOF measurement(s) needs to be transferred from the TDC7201 to the MSP430, and, eventually, sent to the host PC. I don't care whether there is a delay between the measurement and the arrival of the data at the host PC, as long as every Start-Stop-Stop trigger sequence is captured/measured.

Is it reasonable to expect to send USB data-bytes at 240K baud? (30bytes per measurement, one measurement per ms.)

If not, is 100K baud more reasonable? (Processing on the MSP430 can reduce the data to 10bytes per measurement.).

Are the USB "CDC" functions (from USB_Constructs.h) adequate for this required volume of data?

Any help is appreciated..

over 6 years ago

0 Bharat Aravamudhan over 6 years ago

TI__Genius 11015 points

Hello B,

240K baud should be good to read this data. However are you planning to use the GUI or using your own method to read these data.

0 B Lench over 6 years ago in reply to Bharat Aravamudhan

Intellectual 610 points

Hi Bharat,

We're writing the code/firmware that will run on the MSP430F5539 LP. We're also writing the code that will run on PC and interface with that module.

The firmware needs to respond to trigger-events at 1KHz - without missing ANY triggers. It needs to capture and send measurements at 1KHz.

I'm not sure whether any special USB setup/config is required. For instance, can I simply call cdcSendDataWaitTilDone() with 30bytes every 1 ms?

Thanks!

0 Bharat Aravamudhan over 6 years ago in reply to B Lench

TI__Genius 11015 points

B Lench,

This will be a question for our MSP430 team, let me forward your request to them and get their inputs.

0 JD Crutchfield over 6 years ago in reply to Bharat Aravamudhan

TI__Mastermind 29105 points

Hello B Lench,

For developing with the USB on the MSP430F5529, you will be using our MSP430USBDEVPACK. This is maintained inside MSP430 Ware and all the related documentation on the stack itself and API guide can be found there. Here is a link: http://dev.ti.com/tirex/explore/node?node=AAUJ6YInKu.PpzCDv2gn2w__IOGqZri__LATEST

I'm not an expert on the USB stack, but it looks like the function you mentioned is a lower-level function of the driver, so I would recommend using one of the APIs. Maybe something like USBCDC_sendDataInBackground().

For questions specifically about the MSP430 USB that may come up during your development, I would encourage you to search and post the MSP430 E2E forum, here: e2e.ti.com/.../166

Thanks,

Sensors

Sensors forum

TDC7201-ZAX-EVM: Noob to MSP430 (and CCS) seeking advice on USB settings and maximizing throughput/performance.