Author Topic: NHD-0220CW-AB3 "doubling" data?  (Read 1945 times)

GerryO

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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)
Delay
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!


Saurabh_B

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Re: NHD-0220CW-AB3 "doubling" data?
« Reply #1 on: October 22, 2015, 12:07:51 PM »
Hi,

I was wondering if you could share your wiring diagram, along with the initialization sequence you are using.

The initialization sequence for this display will be significantly different compared to the standard character OLED displays.

GerryO

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Re: NHD-0220CW-AB3 "doubling" data?
« Reply #2 on: October 25, 2015, 03:25:07 AM »
Thanks for responding. The wiring diagram & initialization sequence are identical to the datasheet.

When speaking to PaulB on the phone, I mentioned something to him that I should have paid more attention to: when characters were displayed, they appeared to be from ROM C. This is not the ROM selected by the initialization sequence. How could some data be making it in but with wrong (mis-aligned) bits?

A thorough re-examination of the hardware (3rd time!) showed that the connections for #CS & #RES *looked OK* but were actually flaky. Replaced those & the panel is running.

 

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