only half height of font showing on SSH1106 in 4w SW SPI mode

[strud]

I am using an SSH1106 OLED display connected to a Teensy4.1 and running in 4W SW SPI mode with this library.

When I run the basic full buffer Hello World example only the top half of the text is shown, and text on a lower line does not appear at all.
This is a VERY fast processor (600MHz), so as this is a soft SPI implementation, I'm wondering if any delays etc need to be changed?

[olikraus]

More details would be nice: Picture of the output and complete code (including the u8g2 constructor name), which renders the output of the picture.

[strud]

U8G2_SH1106_128X64_NONAME_1_4W_SW_SPI u8g2(U8G2_R0, SCK1, MOSI1, CS2, SDA2, _RESET);

if (loggerConfiguration.expansionType== EXPANSION_BOARD_GUI_SPI){
      sDevice->println("initialising OLED");
      u8g2.begin();
      u8g2.clearBuffer();					// clear the internal memory
      u8g2.setFont(u8g2_font_6x12_tr);	// choose a suitable font
      u8g2.drawStr(0,60,"HiPerDaq (ultra)");	// write something to the internal memory
      //u8g2.drawStr(0,20,"fw ver 1.11");	// write something to the internal memory
      u8g2.sendBuffer();					// transfer internal memory to the display
  }

If I use a bigger vertical offset such as 20, there is no text.

[strud]

Here is a video of the behaviour using the GraphicsTest example without modification, using the same constructor as above code

https://drive.google.com/file/d/1hxe19gH6z9bQrVLmVYc2FHtk2hc47Emw/view?usp=sharing

The behaviour is basically the same, graphics only appearing in the top strip of the screen.

I will build up another one to make sure it isn't a dodgy screen.

[olikraus]

You must use the "F" (full buffer) constructor instead of the "1" constructor.

https://github.com/olikraus/u8g2/wiki/u8g2setupcpp#constructor-name

[strud]

Fantastic, that fixed it. Many thanks

[olikraus]

I have updated the FAQ:

u8g2/doc/faq.txt

Lines 147 to 153 in fe36d90

	Q: Data is written only to the first 8 lines of the display. Why?
	A: U8g2 page mode constructor ("1" mode, see previous question) is used
	along with the "sendBuffer" command. This is a mistake and will not work.
	Solutions:
	1. Change the constructor to full buffer mode: Replace "_1_" by "_F_"
	2. Replace "sendBuffer" with the firstPage/nextPage loop
	See also: https://github.com/olikraus/u8g2/wiki/u8g2setupcpp#constructor-name

I also added a warning into the manual:
https://github.com/olikraus/u8g2/wiki/u8g2reference#sendbuffer

[strud]

Thanks for such great responsivness.

One question though, should #2 be reveresed?

Ie instead of 2. Replace "sendBuffer" with the firstPage/nextPage loop

write 2. Replace firstPage/nextPage loop with "sendBuffer"

?

[olikraus]

oh, yes, thanks. I will fix this.