Digital Discovery - Step Back

[engrpetero]

I'm still learning how to use this Digital Discovery device.  Slow progress. 

Using the Logic Analyzer panel, I've setup the device to do an SPI test where pins DIO 24-27 represent a Master and pins DIO28-31 represent a slave.  I've physically connected pins 24 to 28 (chip select active low), 25 to 29 (sclk), 26 to 31 (MOSI), and 27 to 30 (MISO). 

To see something working, I then used the Pattern Generator panel and setup a bus on pins 24-27 to perform an auto-repeat Binary Counter at a frequency of 500KHz.  I click 'Run' on the Logic Analyzer, then I click 'Single' on the Logic analyzer.  I get the following (which seems to indicate things are working and the appropriate pins are connected together (sorry the picture is small but there was a lot on the screen).

Since the pattern generator seemed to provide expected results, I clicked 'Stop' on the pattern generator.  I then used the Protocol panel to attempt to send 4 bytes over the SPI interface.  I click 'Single' on the Logic Analyzer and the Logic Analyzer indicates 'Armed'.  I then click 'Execute' in the Protocol panel, the Protocol panel shows the bytes written, shows 0x00 for the bytes read, and the Logic Analyzer just shows 'Busy' (see next screenshot).

I looked in the help at the states for the Logic Analyzer and 'Busy' isn't mentioned.  I never see any transitions in the Logic Analyzer and I've waited up to several minutes to see if the 'Busy' indicator ever changes.  It doesn't.  I can click 'Single' or 'Run' and the Busy indicator goes away.  But I never see any waveforms appear.  I figure I'm close to getting the result I expect but must be doing something stupid and though probably obvious, escapes me.  Any assistance, please?

[attila]

Hi @engrpetero

The Protocol tool uses the device Pattern Generator and Logic Analyzer resources. When the Protocol is used the Patterns and Logic show Busy state.
When the "Debug with Logic Analyzer" option is enabled, the Logic Analyzer can be used to investigate the signals. In this case, the Protocol instrument will not receive data, it will only send data.
You can have multiple instruments open and the last used takes control over the specific device resource.

[engrpetero]

Wow - that is super helpful.  Thanks Attila!  If I close the Logic Analyzer panel and then click the Protocol panel 'Debug with Logic Analyzer' button, that button turns green, the text changes to 'Debug with Logic Analyzer. No Data Reception!'.  And a Logic Analyzer window opens showing the expected Master SPI bus.  When I click 'Execute', the SPI transfer shows in the Logic Analyzer.  

For kicks, is there a way to also show the Slave interface in that logic analyzer (since if have the pins 24 connected to 28, 25 to 29, etc.)?

 

[attila]

Hi @engrpetero

Enabling "Debug with Logic Analyzer" will open a Logic interface if it is not already open and add the currently used protocol and options.
After that, the Logic settings can be modified and additional interpreters can be added.

[engrpetero]

Excellent.  Making good progress now.  Thanks again for the help, @attila.

Edited January 10 by engrpetero