XMOS startKIT: XMOS and Raspberry Pi Oscilloscope XAE 1000

RE: XMOS startKIT: XMOS and Raspberry Pi Oscilloscope XAE 1000

Former Member — Mon, 29 Dec 2014 17:48:43 GMT

Hi, I'm following your project but have come across some difficulties.

I've got the code compiled and running on the Pi and the XMOS board. I can see the Pi is polling the SPI interface, but is getting zeros returned on the MISO line. This has been confirmed by doing ./xmos_adc.

If I hardwire the MISO line from Pi to 3.3v, the I read 0xff's instead of 0x00. So the Pi SPI input seems to be working.

If I add some of your commented-out printf() calls back into the XMOS code and run it from the GUI, I can see

App started

incoming SPI

but that's all.

I have applied a sine wave which is level shifted to lie between approx 1v and 2v as I assume the ADC0 input has a max FSD at 3.3v? Can't find this documented ..

Can you suggest how to go about debugging this?

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Update: I tried using this simple program: http://www.xcore.com/forum/viewtopic.php?f=44&t=2537

I added the -fxscope parameter to the makefile, and it works (between 1 and 9 LEDs light up depending on the voltage on ADC0).

So there must be some difference in the way this is using the ADC.

RE: XMOS startKIT: XMOS and Raspberry Pi Oscilloscope XAE 1000

clem57 — Sat, 22 Nov 2014 03:24:43 GMT

I like the elegance of the interface [mention:b0bc65b9ecdc4307bd967592f00e340a:e9ed411860ed4f2ba0265705b8793d05] used. I am getting SPI under my belt and see a lot of uses like the ones here. When I get a BitScope micro (hopefully soon), I will write more about this topic..

Cheers,

Clem

RE: XMOS startKIT: XMOS and Raspberry Pi Oscilloscope XAE 1000

DAB — Sun, 22 Jun 2014 18:45:30 GMT

I wonder if the same thing could be done with the RIOT Board?

DAB

RE: XMOS startKIT: XMOS and Raspberry Pi Oscilloscope XAE 1000

Problemchild — Sun, 22 Jun 2014 14:47:38 GMT

Thanks again for an excellent article sized blog post [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-d7de46e9-b3fa-4f73-a90a-a1ee5cba2948/contentimage_5F00_1.png:16:16]

I particularly like the photo showing the SPI connection to the RPI, yes it really is that simple!!

Often folk get it into their heads that it's all super complicated, but the flexibility of the Soft I/O on the

XMOS makes it ridiculously easy to get even high speed I/O running.