CFAL12864N-A-B1 128x64 Graphic OLED module doesn't turn on


New member
Hi! I'm new using LCD modules. I'm trying to use a CFAL12864N-A-B1 128x64 Graphic OLED module but the problem is that the device never turns on.
I connect Vpanel to 9V, Vlogic to 3.3V, and I use 4.4 uF capacitors connected to Vbref, Vcomh and Vpanel. I also use 950 Kohm connected to the Iref pin.
I noticed that Iref current isn't 10 uA as specification recommend, it is only a few nA.
I'm using Serial communication by the SPI of a PIC32.
What am I doing wrong? I would appreciate your response.
Thanks a lot

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I will try to help you troubleshoot. Please answer these questions.

1. Are the IS1 and IS2 pins set to gnd for serial operation?
2. Are you using D0 as clock and D1 as data for the SPI connection?
3. Is the SPI clock configured for rising edge?
4. Is the SPI clock speed set to less than 4 MHz?
5. Are you sequencing the Vlogic and Vpanel as shown on Pg 13 of the data sheet? "Display must be powered up and initialized before power is applied to the Vpanel pin."
6. Have you tried using the sample code on Pg 27-31 of the data sheet?


New member
Hi again! finally, the oled module turns on. It's externally powered (Vpanel = 9V) and it works perfectly. But now I want to use the built-in DC-DC voltage converter and it's not working.
There is a post in this forum about the CFAL9664B-F-B1 and it says "the documentation indicates that the controller contains a DC-DC converter to generate the 12v needed for the display, but the converter is not implemented with this display"; now, I was wondering if it's the same problem with the CFAL12864N-A-B1 oled module I'm using, since I checked all connections and they're right. I followed the connection schematic provided in the module datasheet, as well as the diagram with the recommended steps of initialization.
I attach the schematic and code used

Does anyone work with the built-in DC-DC?

What could be the problem?




New member
I also checked SW and VBREF pins and they're both at 0V. I think that at SW pin it should be a square wave signal and VBREF should be at least 1V. So thes all indicate as the built-in DC-DC is off.
What can I do?

CF Support

Unfortunately, the quote from the CFAL9664B-F-B1 - "the documentation indicates that the controller contains a DC-DC converter to generate the 12v needed for the display, but the converter is not implemented with this display" is also true for this part, in so many words.

I will make sure that this is noted in the datasheet explicitly, but the pins required to make the internal DC-DC converter work are not all brought out, making it impossible to use it either way.

Sorry for the confusion.


New member
Initialization and power sequencing ...


The datasheet is clear that vPanel must be turned on 100mS after vLogic ... I'm doing that, but not getting results.

SPI interface (IS1 = IS2 = low), slowed down to 1MHz, rock-solid signal levels, no glitches, I"m following the initialization sequence in the user guide except ... I have vLogic controlled by RST and I hold RST low for >100mS at powerup to meet the minimum delay time. But vPanel is on as soon as RST is released.

It is essential that the control registers are configured before vPanel is applied? Pg 13 only specifies a 100mS delay and does not talk about initializing the control registers before turning on vPanel.

I also have RD and WR floating (not used with SPI), but the SH1101A datasheet seems to indicate they should be tied high or low - any chance that's the issue?


New member
CFAL12864N-A-B1 and CFAL12832-C-W-B1

Hanging my head in shame ... I got mixed up with the pinout - the folded FPC led me to flip pins 1 and 27 - even though they are marked on the part!
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