Hello, I am reading a large amount of analog data with my PSoC 5. I would like to save this data and view it on my PC.

I am collecting 40,000 samples per second. (1 byte per sample)

What would be the easiest way for me to transfer this data to a PC? I was thinking I should use the USBUART module, but it is kind of complex and I wanted to make sure this was really the best solution before pursuing it further.

Thanks,

Grant

 Actually, it looks like it will be closer to 200k samples per second at 1 byte per sample. So the data connection will need to support 200 KBps or 800 Kbps. Not sure if that changes anything.

 Please see this video first:

www.youtube.com/watch

800kbps is pushing the limits of UART, which is one of the most common embedded-to-computer comm protocols. Although they do support 921600 baud, aka 921.6kpbs, I havn't had much luck running the UART at this high speed, and get corrupted data. You also have to consider start/stop bits and other overhead.

Maybe try your luck with an SPI interface. The SPI component in PSoC Creator can support your required baud rate, so all you need to find is an SPI-to-USB interface to plug into your computer. 

Another option could be the USBUART component, which emulates a COM port, communicating through USB to Virtual COM ports on the computer. I couldn't find the max supported speed on a quick look at the datasheet.

The USB protocol could be another way to go, although you did specify you wanted "simple". 

200k samples per second mean you need to push at least 1.6mbit/second to the PC (maybe even more when you count in overhead). This will be difficult to get with USBUART on a constant basis - typically these protocols send one USB packet per transmitted byte, which gets you high latency.

You will need to test this and check that you can the the desired performance.

Otherwise, SPI will be simple from a PSoC perspective - but on the PC side it will be more complicated.

The best way would be, IMHO, to use pure USB communication. You can do bulk transfers, and can be sure to get the transfer speed you need.

A problem on the PC-side will be that you do not have a real-time operating system, but a multitasking Windows. Besides checking for latest updates for your software, windows runs ~100 processes which will take some MIPs delaying the transfer of your Data or rather: slicing the transfers into packages which are difficult to predict when get transferred.

Since you are probably not measuring 24 hours a day, you can estimate the overall amount of data that needs to get buffered and choose an adequate medium (ie. SRAM ) to temporarily store the information. I think, you'll have to dig deep into the trick-box and pull out some of the procedures (double buffering, circular buffers, interrupt driven, DMA) to get your requirements solved.

Bob

@Quick: can you tell us a little bit about what you want to do? How are these samples generated, and how long will the measurement process last?

Usign UART you won't get transfer rates higher than 5KBps.

Generally, the easiest way to pass data to a computer is using the USB-HID cass, as you dont have to write drivers. Unfortunatelly, despite it being 10 times faster than UART, you won't be able to get rates of 200KBps. Your best bet is using CDC USB class. Cypress USB suit should help you with that.

 @Bob

You won't notice any performance issue on the Host side. An entry level computer nowadays have much much more prossesing power than required to deal with all threads plus USB. 

on the device side, using 2 DMA channels, the first to move data from ADC to memory and the other to move data from memory to USB endpont, should solve any performance issue.