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Topics - joegangi

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OLEDs / NHD-2.23-12832UCY3
« on: January 10, 2018, 04:11:56 PM »
I am using the NHD-2.23-12832UCY3 in a new product design. I am using the SPI interface. I tried using the prescribed initialization sequence for the SSD1305 as prescribed on page 13 of this product's data sheet. When this sequence is executed nothing shows on the display. I found that all I have to do to get the display to operate in an acceptable manner is to pulse the hardware reset line (16) low, then send the Set Display On Normal command ( op code 0xAF). After this I can load data into RAM and the corresponding image shows on the display. With the possible exception that it might be upside down (there is no indication in the 12832UC data sheet as to which way is "UP" on this display.

What is the purpose of the elaborate initialization sequence given on page 13 if the display can be enabled so simply as resetting it and issuing the 0xAF command?

A further problem I am  experiencing is that the display reacts to the Contrast command ( 0x81) by dimming and brightening as the associated contrast value is changed. However, the display does not react to the Brightness Command (0x82) at all. Is this somehow related to my "abbreviated" initialization sequence?

A related question: What is "contrast" in an OLED display? Is it the ratio of brightness of an  ON pixel vs an OFF pixel? Or, is it a ratio of brightness of an ON pixel vs the optical background of the display field?

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