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Topics - GerryO

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OLEDs / NHD-0220CW-AB3 "doubling" data?
« on: October 22, 2015, 02:19:45 AM »
I'm replacing a NHD-0216KZW-AD5 with a NHD-0220CW-AB3. I'm using a 4-bit 6800 parallel interface. The current software works fine with the 0216 display.

I've changed the wiring for the 0220's interface & checked everything 3 times, especially the BS0-2 lines. The problem is that whatever character is sent to the display is interpreted as 2 characters: sending 0x61 results in the characters 0x66 & 0x11 being displayed. Apparently every data nibble sent is being captured twice as a byte???

Yes, I have the unused data lines (D3-D0) tied to ground.
Yes, I've tried both "Condition 1" and "Condition 2" timing in the 0220 manual -- doesn't matter.

Existing initialization sequence looks like this (works for 0216 & other non-NHD displays):

Send data: (0x03, 0x03, 0x03, 0x02)
Send command: (0x28, 0x08, 0x06, 0x17, 0x01, 0x02, 0x0C)

I tried replacing the initialization sequence with the one at the back of the 0220 datasheet but I usually don't get any characters at all (sometimes what looks like noise).

Any suggestions would be very welcome!

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