Problem interfacing to CFAL25664A-Y-B1

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charlievictor102

New member
Any idea of why the screen refresh rate seems to be so slow?

Here is a video of what I’m seeing:
http://youtu.be/gzFUcZbIWsI

I’m trying to get the example code to work. I’m using a Freescale MC9S08GB60 microcontroller. Talking to the OLED display via the parallel interface. The flickering is not just aliasing with the video. It actually looks like the screen refresh rate is around 5Hz.

If I change the “clock divider ratio” (SDIV) field in the SCLKDIV register there seems to be no effect.

Also, it looks like there may be some garbling of the image as compared to the CFAL25664A-Y-B1 web page.

Any ideas? Should I post the code?
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charlievictor102

New member
I figured out my problem. I’m bit-banging the parallel interface by flipping the microcontroller GP IO lines to drive the CS*, WR*, SD/C*, and data lines. I needed to put a bunch of NOPs (3.5us worth) to delay the rising edge of the WR* signal from the time I start driving the output data on the data lines. I think the data sheet says this (Tds) should be 60ns. My prototype hardware is driving the signal about 6 inches but I would think that would not add that much time.

So I have the display working. It looks really good - thanks Crystalfontz. One mystery solve but another (minor) one remains (why the 3.5us). I’m wondering if I can read the data back out of the display buffer (really limited RAM in the uC) – can’t really tell from the datasheet. I need to do some tests of that.

Is anyone interested in seeing the code on how I did this (CFAL25664A-Y-B1 display, MC9S08GB60 microcontroller (LS08), parallel interface)? Should I post the code here?
 
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