No pin activity sm 3.2 with v4 commented out


#1

I have installed arduino 1.88 with smartmatrix 3.2 from the master github. I am using a teensy 3.2
I am testing with the featuredemo.
If i comment out the v4 line, i get no signals on pin 14 (CLOCK). I get a 3khz on pin 13 and 23, 22, 9 and 10. I get nothing on the rgb pins.
If i leave the v4 line enabled, the rgb pins, clock and latch oe work fine. I get no addx pins, though.
Is this a known problem with sm3.2?
I would like to use a sm v3 shield but it appears the teensy is stuvk or crashed or something with v4 disabled.


#2

V4 requires external parts.

V3 requires connecting the latch signal between two pins, did you follow this diagram?

http://docs.pixelmatix.com/SmartMatrix/shieldref.html#smartled-shield-formerly-smartmatrix-shield-overview-technical-details-manually-connecting-teensy-and-panel


#3

Yes. I am connecting pins 3 and 8 to get the latch from both sources, but that isn’t the problem.

The problem is that when the v4 line is commented out I don’t get any waveform from the RGB pins or the clock pin. I get a waveform from the 4 address pins but they are the same (not powers of 2 different as I would expect).
It is like the teensy has crashed and is not progressing after setting up some initial settings.
The other thing that is different with v4 enabled is that the LED (Pin 13) flickers on startup and then settles down to an apparently steady light (It is actually a 3KHz signal).

When I enable the v4 line, I get outputs like I expect (except there are no address pins). The RGB lines give waveforms that change over time (meaning that the program is running properly). The clock gives a 5MHz or so clock signal.

I have wired my project to use the v3 pinout and would prefer to keep it that way.


#4

I haven’t seen this issue before. I’d double check that pin 3-8 connection, as that is something that will break the refresh code if one of those lines is stuck waiting for the signal to toggle on the other line

Do you have the same issue (no fast CLK signal) if the matrix and any other hardware is removed from the Teensy?


#5

I tried again last night with a brand new teensy 3.2 not connected to anything (including no 3-8 bridge). That is where I got the behavior I described.

If this is not normal and https://github.com/pixelmatix/SmartMatrix is the correct location for the code, then i’ll try with a fresh arduino/teensyduino install on another computer.


#6

including no 3-8 bridge

That likely explains the problem. That’s where the code lives on GitHub, download a zip from the “Releases” page for best results.


#7

That’s what it was (the 3-8 bridge missing).
Without the bridge, something that should have been clearing swapPending didn’t happen - causing swapBuffers to stick.

Now that it running, I see a clock of 5 to 6 MHz on pin 14.
That speed might be too fast for the HC244s in the old panel i’m driving.
Do you know what setting I can adjust that would cut that clock speed in half?
(adding Serial.println s in the swapBuffers function for debugging did the trick, but that doesn’t seem like the proper way to slow it down).,


#8

Change 0x02 to 0x03 in this line to divide the CLK speed in half