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NT7108-12864LCD

I was given a LCD module. Took quite some time to get it running.

Finding documentation

The display came from and original factory box.

box

The stamp shows the manufacturer name: POWERTIP. There is also a type indication PG12864WRF-JNN-H-P5.

On the backside of the module there is similar information. POWERTIP PG12864J-P5(1.1) and PG12864WRF-JNN-H-P5.

module

Some Googling revealed a datasheet. The datasheet mentions controller ICs NT7107, NT7108. I also found that datasheet.

I was confused about seeing two controllers (NT7107 and NT7108). At this moment I believe it works as follows: A single NT7108 can drive 64 columns of 64 rows. So for a 128x64 display we need two NT7108. However, the module also needs a row driver. A single NT7107 drives 64 rows, the row driver is controlled (and shared) by the column drivers.

System

Wiring

I found some libraries for Arduino. One from simple-circuit and also the famous u8g2 from olikraus. But at first both failed to work (and now, the "simple circuit" one still swaps columns).

The biggest issue turned out the wiring. This is how I wired to get my sketch running.

  • Section 2.2.1 of the datasheet indicates a VDD of 5V (4.5V-5.5V). So I did my experiments with an Arduino Uno (that is 5V, unlike eg an ESP32). Please note that the NT7108 datasheet lists as VDD from 2.7V to 5.5V, so maybe an ESP is possible after all.

    • Pin 1 VDD (supply voltage) needs to be wired to Uno 5V.
    • Pin 2 GND (ground needs) to be wired to Uno GND.

  • Section 2.2.1 of the datasheet explains how to power the backlight.

    • Pin 20 BLK (backlight kathode) needs to be wired to Uno GND.

    • Pin 19 BLA (backlight anode) needs to be wired to 3V3. An Arduino UNO has a 3V3 out pin. No resister seems necessary.

    • A potmeter (10 to 20 kΩ) needs to bridge Vee (pin 18) and VDD (pin 1), the varying pin goes to Vo (pin 3).

      backlight

  • The module is a parallel module (8 lanes).

    • Pin 4 DB0 (data bus bit 0) needs to be wired to Uno GPIO 2.
    • Pin 5 DB1 (data bus bit 1) needs to be wired to Uno GPIO 3.
    • ...
    • Pin 11 DB7 (data bus bit 7) needs to be wired to Uno GPIO 9.

  • There are seveal control lines.

    • Pin 12 CS1 (chip select first column driver) needs to be wired to Uno GPIO 10.
    • Pin 13 CS2 (chip select second column driver) needs to be wired to Uno GPIO 11.
      Note that I had to swap CS1 and CS2.
    • Pin 14 RST (reset) needs to be wired to Uno GPIO 12.
    • Pin 15 R/Wn (read/write select) needs to be wired to Uno GPIO 13.
      Note that the U8g2 library does not use R/Wn, it needs to be grounded. I connect it to GPIO 13 and below Arduino sketch pulls that pin down in setup().
    • Pin 16 D/In (data/instruction select, aka as data/command select), needs to be wired to Uno A0.
    • Pin 17 ENA (enable), needs to be wired to Uno A2.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
5V GND Vo DB0 DB1 DB2 DB3 DB4 DB5 DB6 DB7 CS1 CS2 RST R/Wn D/In ENA Vee BLA BLK
5V GND pot2 2 3 4 5 6 7 8 9 10 11 12 13 A0 A1 pot1 3V3 GND

Firmware

The U8g2 library is a likely candidate. Unfortunately, it does not list NT7108. However, somewhere I found a snippet saying that BT7108 is a KS0108 clone. With that, I got the U8g2 lib working.

With the above wiring, this is the constructor call

U8G2_KS0108_128X64_1    u8g2(  /*rotation*/ U8G2_R0,        
  /*DB0..7=*/ 2,3,4,5,6,7,8,9, 
  /*enable=*/ A2, 
  /*D/In=  */ A0, 
  /*CS1=   */ 11, 
  /*CS2=   */ 10, 
  /*CS3=   */ U8X8_PIN_NONE, 
  /*RST=   */ 12);   
  /*R/Wn=  */ // This library does not use it; connect to GND on the PCB!

The setup() takes care of grounding R/Wn.

void setup(void) {
  pinMode(13, OUTPUT); digitalWrite(13, 0); // R/Wn tied to GND
  u8g2.begin();  
}

The loop() draws the test screen.

void loop(void) {
  u8g2.firstPage();
  do {
    u8g2.setFont(u8g2_font_ncenB10_tr);
    u8g2.drawStr(5,20,"Elektro Club");
    u8g2.drawStr(18,40,"de Pracht");
    u8g2.drawFrame(0,0,128,64);
    u8g2.drawFrame(2,2,124,60);
    u8g2.drawXBM( 93, 27, u8g_logo_width, u8g_logo_height, (uint8_t*)u8g_logo_bits);
  } while ( u8g2.nextPage() );
}

which results in

demo

The full sketch is available.

Of course, it also runs on Nano.

nano

(end of doc)