Digital Discovery and SPI MOSI/MISO acquisition

[Kam]

Hi everyone,

I hope you are all doing well 😀

I just purchased the Digital Discovery, and am trying to capture SPI MOSI/MISO data. I'm using the Waveforms tool version 3.19.5

My spi bus baud rate on my micro (PIC32MZ) is set at 1mhz. Everything is working fine, and I can read the MISO data on the micro and everything looks great.

I'm trying to learn the tool on a working setup, and I'm really having a difficult time just trying to acquire the SPI data in waveforms.

I would like to do lets say a 30 second capture, my program on the micro calls the SPI device 2 times per second (2Hz), so that would be 60 SPI calls.

I just cannot figure out how to configure waveforms to do this 😲

Also, one the few captures I was able to do, when I looked at the "data" windows of the SPI data, is there any way to only how me the MISO data, and not the "dead" frames?

Any advice would be greatly appreciated.

~Kam

[artvvb]

Hi @Kam

The protocol analyzer instrument ("Protocol" in the welcome tab) should be able to do what you are looking for. Below are a couple of screenshots of two devices, one of which is generating a sequence of SPI master frames at the time interval you mention, and the other recording them.

Thanks,

Arthur

 

SPI master:

SPI Spy:

[Kam]

17 hours ago, artvvb said:

Hi @Kam

The protocol analyzer instrument ("Protocol" in the welcome tab) should be able to do what you are looking for. Below are a couple of screenshots of two devices, one of which is generating a sequence of SPI master frames at the time interval you mention, and the other recording them.

Thanks,

Arthur

 

SPI master:

SPI Spy:

Hi Arthur,

Thanks for the reply and answer! Yes, this meets the bill perfectly. Interesting that my version of Waveforms BETA (latest as of this writing), is a tad different then yours. I had to use DIO24/25/26/27. BTW, it looks like the default for DQ0 was 25 instead of 26. Also, without custom programming, can I remove the dummy value from the display?

Data: b11111111 | b00000000, b11111111 | b11111100, b11111111 | b00010011, b11111111 | b11000000,

the 0xff is the default dummy SPI value from the Micro SPI...

it would be nice to get just the 4 8-bits

Data: b00000000, b11111100, b00010011, b11000000,

 

ALSO, funny enough, I've been using 0xDEADBEEF since the 80's when I starting in C and needed magic numbers...😁

thanks again,

 

~Kam

 

[attila]

Hi @Kam

On Digital Discovery the DIOs are labeled from 24.

The printed Data is MOSI|MISO, ... 
If you are not interested in MOSI select Mode: Three-wire and only use DQ0.

[Kam]

6 hours ago, attila said:

Hi @Kam

On Digital Discovery the DIOs are labeled from 24.

The printed Data is MOSI|MISO, ... 
If you are not interested in MOSI select Mode: Three-wire and only use DQ0.

Interesting...when I select the 3 wire mode, I only see the "dummy data" of 0xff, not MISO

Data: b11111111, b11111111, b11111111, b11111111,

if I change my dummy data, the above follows that value...

[attila]

Hi @Kam

Change DQ0 to be the MISO.

[Kam]

8 hours ago, attila said:

Hi @Kam

Change DQ0 to be the MISO.

That did the trick! Perfect 😁

Data: b00000001, b00010100, b00010011, b10010000,

~Kam