NHD-0420CW-AG3 MPU Interface Pin Selection and Power Supply

[blaubaer]

Hi,

for 8-bit parallel 6800 interface mode the NHD-0420CW-AG3 display spec shows for pin BS0 = 0, BS1=0 and BS2=1 - can I connect BS0 and BS1 to ground and BS2 to +5V to switch the display into the 8-bit parallel 6800 interface mode? Do I need pull up/pull down resistors - with which value?

For +5V power supply I've to connect +5V to pin 3 and let pin2 without connection, right?

Thanks and regards,
Michael

[Retheesh_M]

You are correct.  To enable the 8-bit parallel 6800 interface you would connect BS0 and BS1 to ground and connect BS2 to +5V.  You don't need a resistor on BS2.

You are also correct that pin 2 should not be connected if you are going to use a 5V power source to power the display.  Only pin 3 needs to be connected to +5V.

[blaubaer]

Dear Reteesh,

thanks for the quick response!

The NHD-0420CW-AG3 display is still not working. Let me shortly point out what I did so far:

I've the NHD-0420DZW-AY5 display in use in my application and it's working fine. Now I saw the NHD-0420CW-AG3 within your OLED display product range and would like to take this display, because the pcb and the display itself is smaller and fits mechanically better into my application.

The NHD-0420DZW-AY3 spec says, that the display is by default in 6800-MPU parallel interface mode, so I set the NHD-0420CW-AG3 with connections pin BS0 and BS1 to ground and pin BS2 to +5V into the same interface mode, connected pin 3 to +5V, did not connect pin2, connected RS to D/C (pin4), R/W, E, the data connections and ground to pin 1 and 20.

What did I wrong? Do you have an idea?

Thanks and regards,
Michael

[Retheesh_M]

On the new display (NHD-0420CW-AG3) there are two additional pins:

Pin 15 = CS (Chip Select) Active LOW
Pin 16 = RES (Reset Signal) Active LOW

Have you set these pins?  If not then set CS to LOW and RES to HIGH. 

[blaubaer]

Hi Retheesh,

On the new display (NHD-0420CW-AG3) there are two additional pins:

Pin 15 = CS (Chip Select) Active LOW
Pin 16 = RES (Reset Signal) Active LOW

Have you set these pins?  If not then set CS to LOW and RES to HIGH.

no, but I'll do that immediately! 

Thanks so far,
Michael

[blaubaer]

Hi Retheesh,

now basically it works, but characters are mirrored - I will recheck the solder joints....

Regards,
Michael

[Retheesh_M]

Glad to hear you got it working.  When you say mirrored, are you talking about the text printing in the opposite direction (right to left) or that the characters are actually backwards?

[blaubaer]

The text is printed from right to left and in a mirror I can read it...

[Retheesh_M]

Can you post your initialization function?

[blaubaer]

This may take a while - I didn't code it!

I'll come back to you when I got it!

Regards, Michael

[Retheesh_M]

This could be why you're having problems with this board.  Some of our OLED displays require a specific initialization sequence in order to function properly.  For this display, the specification sheet has an Arduino coded initialization function at the end of the PDF, or page 22.  It should help you out on how to create an initialization function.

Edit: Above code is not Arduino code, it is for another development board.  It is there to give you an idea on how the display should be initialized.  I apologize for the confusion.

[blaubaer]

Dear Retheesh,

thanks for your immediate help - really fast response!! Nice support forum here!

I'll check and change the initialization sequence and report the result here later.

Regards,
Michael

[Retheesh_M]

No problem   I also edited my previous post because I said the end of the specification sheet has Arduino code when it is not.  They look pretty similar and that code can be easily changed to fit an Arduino if that is what you are using as an MCU.  Otherwise use it as a guide to help you code an initialization function to fit your MCU.  I apologize for the confusion.

[markdpend]

Hi, What happens if one does connect pin-2 to VDD?

[oldmaker]

Hi, markdpend.
It's OK: Newhaven updated the datasheet.
This is the correct configuration:

- 5V operation:
OLED pin 1  ->  VSS   Ground
OLED pin 2  ->  VDD   +5V
OLED pin 3  ->  REGVDD   +5V

- 2.8V operation:
OLED pin 1  ->  VSS   Ground
OLED pin 2  ->  VDD   +2.8V
OLED pin 3  ->  REGVDD   0V