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Messages - EK701

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OLEDs / NHD-2.7-12864UCY3 brightness/contrast adjusting
« on: September 04, 2014, 11:57:57 AM »
Is the 0x81 command the correct one to adjust the brightness/contrast on the NHD-2.7-12864UCY3?  If not, what is?  What is the acceptable range?  0-255? 

OLEDs / Re: NHD-2.7-12864UMY3 - VDD short to VSS
« on: August 26, 2014, 09:36:52 PM »

OLEDs / Re: NHD-2.7-12864UMY3 - VDD short to VSS
« on: August 24, 2014, 09:35:12 PM »
It looks like U1 is the problem.  I couldn't read the marking on it.  Can anyone tell me what this device is so I can replace it?  On a NHD-2.7-12864UCY, the same device (U4) is only marked BLCVA and I can't find any info on that.

OLEDs / Re: NHD-2.7-12864UCY3 ground question
« on: August 06, 2014, 11:30:34 AM »
Thank you!

OLEDs / NHD-2.7-12864UCY3 ground question
« on: August 05, 2014, 07:19:05 PM »
Is there any reason I can't tie all the grounds to together at the NHD-2.7-12864UCY3 and only run one ground wire to the MCU?

OLEDs / Re: NHD-2.7-12864UMY3 - VDD short to VSS
« on: July 29, 2014, 09:30:31 PM »
Just a follow up.  I removed C1 and C2 and the short still persists.  I did find a few interesting things with further testing.  With 3.3VDC applied to pin 2 and pin 1 connected to ground on the power supply, I was able to consistently measure 45mV on all ground points.  Additionally, as soon as I connect the display to 3.3VDC, the voltage displayed on my multimeter drops to .74VDC.  As I probed around the display PCB, occasionally I would see 2+VDC where I should see 3.3VDC, but it would just be a fleeting reading, then drop to .74VDC.  Putting the scope on various points did not show anything of interest - no ripple, no AC, etc. 

One other interesting point is using my multimeter to check continuity, on the tone setting, produced a clear steady tone anywhere on the ground circuits (with the negative lead connected to pin 2).  However, when I put the positive probe onto any part of the 3.3v circuit, it produced a buzzing tone.  Not sure what that means or if it's even of interest. 

I also checked all the components closely under magnification and did not see any that appeared to be burned.  I guess at this point, I'm going to write off this display and purchase another.  Unless someone has any other ideas.

OLEDs / Re: NHD-2.7-12864UMY3 - VDD short to VSS
« on: July 29, 2014, 02:18:01 PM »
Anyone have any ideas?  Does New Haven participate in the forum?

OLEDs / NHD-2.7-12864UMY3 - VDD short to VSS
« on: July 26, 2014, 06:44:27 PM »
I've been using an NHD-2.7-12864UMY3 to do a bunch of prototyping and I think I've managed to cause an electrical issue with it.  With the display not connected to anything, there is a short between VDD (pin 2) and VSS (at any VSS point on the display PCB).  Resistance is about 45 ohms.  I've visually inspected everything, but I don't see anything obviously wrong.

Is there any way for me to trouble shoot this (schematic available?)

OLEDs / Re: NHD-2.7-12864UMY3
« on: June 05, 2014, 11:01:09 PM »
Thank you, that helps!

The U8glib does the following (

/* */
u8g_pgm_uint8_t u8g_dev_ssd1325_2bit_nhd_27_12864ucy3_init_seq[] = {
  U8G_ESC_DLY(10),              /* delay 10 ms */
  U8G_ESC_CS(0),                 /* disable chip */
  U8G_ESC_ADR(0),               /* instruction mode */
  U8G_ESC_RST(1),               /* do reset low pulse with (1*16)+2 milliseconds */
  U8G_ESC_CS(1),                /* enable chip */
  0x0ae,                                /* display off, sleep mode */
  0x0b3, 0x091,                    /* set display clock divide ratio/oscillator frequency (set clock as 135 frames/sec) */
  0x0a8, 0x03f,                     /* multiplex ratio: 0x03f * 1/64 duty */
  0x0a2, 0x04c,                     /* display offset, shift mapping ram counter */
  0x0a1, 0x000,                     /* display start line */
  0x0ad, 0x002,                     /* master configuration: disable embedded DC-DC, enable internal VCOMH */
  0x0a0, 0x056,                     /* remap configuration, vertical address increment, enable nibble remap (upper nibble is left) */
  0x086,                                /* full current range (0x084, 0x085, 0x086) */
  0x0b8,                                /* set gray scale table */
      //0x01, 0x011, 0x022, 0x032, 0x043, 0x054, 0x065, 0x076,
      0x01, 0x011, 0x022, 0x032, 0x043, 0x054, 0x077, 0x077,            // 4L mode uses 0, 2, 4, 7
  0x081, 0x070,                    /* contrast, brightness, 0..128, Newhaven: 0x040 */
  0x0b2, 0x051,                    /* frame frequency (row period) */
  0x0b1, 0x055,                    /* phase length */
  0x0bc, 0x010,                    /* pre-charge voltage level */
  0x0b4, 0x002,                    /* set pre-charge compensation level (not documented in the SDD1325 datasheet, but used in the NHD init seq.) */
  0x0b0, 0x028,                    /* enable pre-charge compensation (not documented in the SDD1325 datasheet, but used in the NHD init seq.) */
  0x0be, 0x01c,                     /* VCOMH voltage */
  0x0bf, 0x002|0x00d,           /* VSL voltage level (not documented in the SDD1325 datasheet, but used in the NHD init seq.) */
  0x0a5,                                 /* all pixel on */
  0x0af,                                  /* display on */
  U8G_ESC_DLY(100),             /* delay 100 ms */
  U8G_ESC_DLY(100),             /* delay 100 ms */
  0x0a4,                                 /* normal display mode */
  U8G_ESC_CS(0),             /* disable chip */
  U8G_ESC_END                /* end of sequence */

So, it looks like the software is doing the right thing, which makes me think I have a hardware problem still with the connection to the Arduino Micro.

Thanks again for the pointers!

OLEDs / NHD-2.7-12864UMY3
« on: June 04, 2014, 11:50:32 PM »
I'm trying to use the NHD-2.7-12864UMY3 with an Arduino Micro and am having difficulties with the electrical interface.  I am unable to get the display to turn on.  If I provide +3.3VDC and GND to the display, with nothing else connected, should the display light up?  I checked the pins on the PCB on the display and I see +3.3VDC on what I think are the appropriate pins.  Do you have some troubleshooting tips, test points, etc. that would help me out?

A detailed schematic and Arduino code is available here:


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