Dual 64x32, mirrors but won't extend


I’m using a Teensy 3.2 and SmartShield v4 with two 64x32 panels from Adafruit.

If I set kMatrixWidth = 64 the panels are mirrored.
If I set kMatrixWidth = 128 the panels go black.

96 “works” by extending across displays, but mirroring the ends.

I’ve tried lowering color depth and buffer rows but that didn’t help.

Here are my options:

#define COLOR_DEPTH 24                  // known working: 24, 48 - If the sketch uses type `rgb24` directly, COLOR_DEPTH must be 24
const uint8_t kMatrixWidth = 128;        // known working: 32, 64, 96, 128
const uint8_t kMatrixHeight = 32;       // known working: 16, 32, 48, 64
const uint8_t kRefreshDepth = 36;       // known working: 24, 36, 48
const uint8_t kDmaBufferRows = 4;       // known working: 2-4, use 2 to save memory, more to keep from dropping frames and automatically lowering refresh rate
const uint8_t kPanelType = SMARTMATRIX_HUB75_32ROW_MOD16SCAN;   // use SMARTMATRIX_HUB75_16ROW_MOD8SCAN for common 16x32 panels
const uint8_t kMatrixOptions = (SMARTMATRIX_OPTIONS_NONE);      // see http://docs.pixelmatix.com/SmartMatrix for options
const uint8_t kBackgroundLayerOptions = (SM_BACKGROUND_OPTIONS_NONE);


What sketch are you running? Did you try using something simple like Bitmaps?


I modified Bitmaps to display images on the far left of panel 1, the far right of panel 2, and in the center spanning both panels. This appears to be working. Thanks for the suggestion.


BTW – It’s the SpectrumAnalyzer example that is causing me grief.


kMatrixWidth = 115 works
116-117 works, but freezes
greater than 117 gives me a black screen

I agree that this is likely a code issue but I’m documenting this anyway.


32x128 pixels is already pushing the limits on the teensy 3.2. The FFT code for the spectrum analyzer example sketch is also resource intensive. You may have better luck starting with a Teensy 3.5 or 3.6.


I tried it with a Teensy 3.6 and everything works great now. Thank you very much for the suggestion.