Using SSD1331 with teensy 3.0 is VERY slow Moderators: adafruit_support_bill, adafruit

[local_dani_21]

Hi adafruit team

I successfully connected one of you 0.96" color OLED-Displays to an teensy 3.0 http://forum.pjrc.com/threads/14816-Compile-Error-when-wanting-to-use-Adadruits-SSD1331-with-Teensy-3-0?p=18108&viewfull=1#post18108. Unfortunately, the output is very slow (I don't know if it is because of slow reading from sd card or from slow drawing to the display). For a 96x64 (fullscreen)-bitmap it takes about 4.9 sec when writing it with teensy 3.0 (@96MHz) compared to 0.5 sec when drawing it from an arduino (16 MHz).

Do you have any idea what the cause of this could be?

Thanks.

Best regards,

Dani

[adafruit_support_bill]

Is it using software-spi perhaps? PJRC might be better able to answer this one.

[local_dani_21]

No, I use hardware SPI. Paul Stoffregen thought, I should get in touch with you guys. Is there anything to adjust about the display-clock (SSD1331 datasheet says something I don't really understand: 9.1.16 SetDisplayClockDivideRatio/OscillatorFrequency(B3h)).

Thanks, Dani

[adafruit_support_rick]

Actually, Paul Stoffgren asked if Adafruit had been notified of cmason's code fix.

If you are having speed issues communicating with the display, it must be something to do with the software you are using. The display is strictly a slave device - the teensy provides the data communication clock.

The datasheet reference has nothing to do with SPI data communications

[pburgess]

Is hardware SPI being used on the SD interface as well?

Try reading the image data from the card but not issuing it to the display, see what the time looks like.

[local_dani_21]

I connect the SD card over hardware SPI (I use the one on the OLED board). Furthermore I use the bmp-example that comes with the SSD1331-library with only pin numbers changed.

Interestingly, when commenting out the data-push to the display as suggested by pburgess, I see that reading from the SD card and calculating the pixeldata takes 80% of the needed time (~4sec for a 96x64pixel bmp). So I suppose that's where the problem lies. What could be in the way of reading faster? Any ideas?

Thanks a lot,

Dani

[local_dani_21]

Actually, Paul Stoffgren asked if Adafruit had been notified of cmason's code fix.

That's right, I just realized that - I missunderstood his post, I apologize ...!

[paulstoffregen]

I ordered a couple displays. They haven't arrived yet.... but when they do, I'll investigate the slowness.

In the meantime, please merge the C++ pure virtual fix. It's needed to simply compile the code on ARM toolchains, and it's proper C++, even if the AVR compiler doesn't strictly require correct code. Other/newer g++ compilers do require it.