SOLVED - unable to make it work 1.8 SPI TFT 128x160

system · September 30, 2012, 2:40pm

Hi!

I've recently bought this on ebay:
http://www.ebay.com/itm/261081638769?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Unfortunately I'm unable make it work.
I've tried to do it while reading Overview | 1.8" TFT Display Breakout and Shield | Adafruit Learning System
however this obviously doesn't have the same pinout, but I was unable to find any example/hint for this PCB

I linked the VCC to the arduino 5V, so I didn't close JP1.
GND goes to GND
Reset: PIN8
A0(???): PIN7
SDA: PIN5
SCK: PIN4
CS: PIN6

Then installed the Adafruit_ST7735 library, uploaded the example, then nothing happened.

Please advise

Thanks,
DEx-

TCWORLD · September 30, 2012, 4:09pm

As this is a random board off ebay from China that has no documentation or published schematic, it is difficult to say.

There are two things that jump out.

SDA/SCK suggests I2C not SPI, so it may well not work with the adafruit library
If (1) is not the case and it is SPI, the adafruit version of the screen has a Data/Command pin (D/C). IF it is the same controller, it is possible that the pin labeled A0 could an equicavalent to the D/C pin, so you could try wiring that up to pin 7 (EDIT: I have just seen that you did, so clearly it is not).

You will need to supply more info about the screen. For example if it is possible to lift it off the board and take a picture of the back of the display and top of the board, it may help in finding more info.

EDIT: there is a link to the datasheet on the ebay page, along with some sample code, which although is not designed for arduino, it should be possible to convert it to work.

TCWORLD · September 30, 2012, 4:40pm

This is the example code. I have very quickly modified it to work with Arduino.

Disclaimer I didn't write this, and it needs a whole lot of optimisation (quite frankly it it awful coding), but at this point it would be good to know if the display works, and if this code works for the display. If it does, then I might be inclined to rewrite it for you.

const byte reset = 8;
const byte cs = 6;
const byte scl = 4;
const byte sda = 5;
const byte rs = 7;

void write_command(byte c){
  digitalWrite(cs,0);
  digitalWrite(rs,0);
  digitalWrite(sda,bitSet(c,7));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(c,6));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(c,5));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(c,4));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(c,3));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(c,2));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(c,1));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(c,0));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(cs,1);
}

void  write_data(byte d) {

  digitalWrite(cs,0);
  digitalWrite(rs,1);
  digitalWrite(sda,bitSet(d,7));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(d,6));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(d,5));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(d,4));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(d,3));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(d,2));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(d,1));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(sda,bitSet(d,0));
  digitalWrite(scl,0);
  digitalWrite(scl,1);
  digitalWrite(cs,1);
}

void write_data(byte LCD_DataH,byte LCD_DataL)
{
  write_data(LCD_DataH);
  write_data(LCD_DataL);
}

void write_data(byte LCD_DataH,byte LCD_DataM,byte LCD_DataL)
{
  write_data(LCD_DataH);
  write_data(LCD_DataM);
  write_data(LCD_DataL);
}

void Reset()
{

  digitalWrite(reset,LOW);
  delay(100);
  digitalWrite(reset,HIGH);
  delay(100);
}
//////////////////////////////////////////////////////////////////////////////////////////////

void lcd_initial(){
  Reset();

  //------------------------------------------------------------------//  
  //-------------------Software Reset-------------------------------//
  //------------------------------------------------------------------//

  write_command(0x11);//Sleep exit 
  delay (120);

  //ST7735R Frame Rate
  write_command(0xB1); 
  write_data(0x01); 
  write_data(0x2C); 
  write_data(0x2D); 
  write_command(0xB2); 
  write_data(0x01); 
  write_data(0x2C); 
  write_data(0x2D); 
  write_command(0xB3); 
  write_data(0x01); 
  write_data(0x2C); 
  write_data(0x2D); 
  write_data(0x01); 
  write_data(0x2C); 
  write_data(0x2D); 

  write_command(0xB4); //Column inversion 
  write_data(0x07); 

  //ST7735R Power Sequence
  write_command(0xC0); 
  write_data(0xA2); 
  write_data(0x02); 
  write_data(0x84); 
  write_command(0xC1); 
  write_data(0xC5); 
  write_command(0xC2); 
  write_data(0x0A); 
  write_data(0x00); 
  write_command(0xC3); 
  write_data(0x8A); 
  write_data(0x2A); 
  write_command(0xC4); 
  write_data(0x8A); 
  write_data(0xEE); 

  write_command(0xC5); //VCOM 
  write_data(0x0E); 

  write_command(0x36); //MX, MY, RGB mode 
  write_data(0xC8); 

  //ST7735R Gamma Sequence
  write_command(0xe0); 
  write_data(0x0f); 
  write_data(0x1a); 
  write_data(0x0f); 
  write_data(0x18); 
  write_data(0x2f); 
  write_data(0x28); 
  write_data(0x20); 
  write_data(0x22); 
  write_data(0x1f); 
  write_data(0x1b); 
  write_data(0x23); 
  write_data(0x37); 
  write_data(0x00); 

  write_data(0x07); 
  write_data(0x02); 
  write_data(0x10); 
  write_command(0xe1); 
  write_data(0x0f); 
  write_data(0x1b); 
  write_data(0x0f); 
  write_data(0x17); 
  write_data(0x33); 
  write_data(0x2c); 
  write_data(0x29); 
  write_data(0x2e); 
  write_data(0x30); 
  write_data(0x30); 
  write_data(0x39); 
  write_data(0x3f); 
  write_data(0x00); 
  write_data(0x07); 
  write_data(0x03); 
  write_data(0x10);  

  write_command(0x2a);
  write_data(0x00);
  write_data(0x00);
  write_data(0x00);
  write_data(0x7f);
  write_command(0x2b);
  write_data(0x00);
  write_data(0x00);
  write_data(0x00);
  write_data(0x9f);

  write_command(0xF0); //Enable test command  
  write_data(0x01); 
  write_command(0xF6); //Disable ram power save mode 
  write_data(0x00); 

  write_command(0x3A); //65k mode 
  write_data(0x05); 


  write_command(0x29);//Display on
}





void  RamAdressSet(){
  write_command(0x2A);
  write_data(0x00);
  write_data(0x00);
  write_data(0x00);
  write_data(0x7f);

  write_command(0x2B);
  write_data(0x00);
  write_data(0x00);
  write_data(0x00);
  write_data(0x9f);		  
}

void dsp_single_colour(byte DH,byte DL)
{
  byte i,j;
  //RamAdressSet();
  for (i=0;i<160;i++){
    for (j=0;j<128;j++){
      write_data(DH,DL);
    }
  }
}

void PutPixel(unsigned int x_start,unsigned int y_start,unsigned int color)
{
  write_command(0x2a);
  write_data(x_start);
  write_data(0x5f);
  write_command(0x2b);
  write_data(y_start+0x34);
  write_data(0x7F);
  write_command(0x2c);
  write_data(color>>8);
  write_data(color&0xff);

}

void setup()
{
  // This code will only run once, after each powerup or reset of board
  lcd_initial();

}

void loop()
{
  static byte i = 0;
  i += 10;
  // This code loops consecutively 
  delay(100);
  write_command(0x2C);
  dsp_single_colour(i,i);
}

system · September 30, 2012, 7:44pm

Tom, first of all thanks for your support. I didn't think that somebody will ever look so much into this.

Unfortunately the code you posted doesn't work either.
Am I wrong if I think, that connecting only the VCC should bright up the LCD already?
It just remains dark...

Shall I try to lift it off the PCB?

Thanks,

TCWORLD · September 30, 2012, 8:36pm

Does the backlight come on?

system · September 30, 2012, 10:50pm

SDA/SCK suggests I2C not SPI

The datasheet says 4-/3-wire spi, no mention of i2c. If it were truly i2c compliant, it would have used SCL / SDA. SDA can be used to mean serial data for spi. The datasheet you linked to has code to drive this lcd, written (poorly) for C51. It also follows the spi sequence as specified in the datasheet.

You can either port that C51 code to arduino (not difficult) or you can use the adafruit code. Or you can write your own: more fun.

system · October 1, 2012, 12:49am

void write_command(byte c){
  digitalWrite(cs,0);
  digitalWrite(rs,0);
  digitalWrite(sda,bitSet(c,7));

I don't think bitSet() does what you had wanted - it sets the bit specified but doesn't return anything.

A simpler way would be this:

void write_command(byte c) {
  unsigned char mask = 0x80;
  digitalWrite(cs, 0);
  digitalWrite(rs, 0);
  do {
    digitalWrite(scl, 0);
    if (c & mask) digitalWrite(sda, 1);
    else digitalWrite(sda, 0);
    digitalWrite(scl, 1);
    mask = mask >> 1;
  } while (mask);
  digitalWrite(cs, 1);
}

Make similar changes to the other routines.

Most of the times, you will need to start with initialization routines to make sure that they conform to the datasheet.

system · October 1, 2012, 5:09am

No there is no backlight!
Is it already bad?

TCWORLD · October 1, 2012, 6:37am

yup sorry, that was supposed to be bitRead(). I always get those mixed up. As I had said though that piece of code needs a complete rewrite, it was just a 2 minute port from the example to arduino.

If the backlight doesn't come on when power is applied, you may wan't to check your wiring to make sure everything is correct. One thing to note is that the backlight needs to be connected to between 3.0V and 3.3V

system · October 1, 2012, 10:52am

Nothing to be sorry about as we all make mistakes.

The bitSet() routine is said to return nothing so presummably it is prototyped as void. Yet digitalWrite() requires a value for its 2nd argument and I was curious as to why the compiler did not complain about that inconsistency.

system · October 1, 2012, 11:22am

The wiring is o.k... at least the power I can measure 5V between the VCC and GND with a multimeter on the pins of the PCB.
But actually I connected it to arduino 5V as the JP1 is open and according to the description in this case 5V must be supplied to the board.

I guess there is no separate pin for backlight and we are talking about the VCC...

Anyway, thanks guys for the sample codes I wouldn't try them out as long as this backlight issue is not solved...

Thanks,

TCWORLD · October 1, 2012, 1:14pm

There is a very distinct difference.

There are two pins labeled LED+ and LED-. These are for the backlights - LED+ goes to +3.3v, LED- goes to GND.

system · October 1, 2012, 2:46pm

This sounds very logical, I'll try that at home, thanks!

system · October 1, 2012, 3:01pm

"LED+ goes to +3.3v, LED- goes to GND."

I would put a resistor there, to get a sense of the forward voltage drop on the diode first.

Just to be safe.

TCWORLD · October 1, 2012, 4:38pm

There is a 100 ohm resistor on the PCB, unless I misread the schematic. I'll check.

TCWORLD · October 1, 2012, 5:18pm

Its a 10 ohm resistor. But the LED is rated at 3.3V with a current rating of 30mA (two LEDs of 15mA in parallel). So at 30mA, the Resistor would drop 0.3V giving the LED a voltage drop of 3V which is well within spec.

system · October 1, 2012, 7:07pm

Thanks guys all your support.
I connected the LED pins, then I've tried out again the adafruit example and everything works now!

Big thanks to all of you!!!

TCWORLD · October 1, 2012, 7:33pm

I'm glad it is working for you. And I am also glad the adafruit library works with the display so you don't have to use that awful sample code!!

DerekD · January 6, 2013, 4:33am

I realize this topic is months old, but I cannot get this module working. I've hooked it up as in the original posting and all I get is a white screen. I'm curious as to whether A0 on the lcd is actually the same as the D/C on the adafruit module and if MOSI and SDA are the same. From what I've found online these last two are probably interchangeable. Has anyone else gotten these to work? I've got three of them sitting here and am at a total loss. Thanks in advance for all the help.

pito · January 7, 2013, 6:44pm

The module works fine here with adafruit's libs and following wiring (328p Uno):
SW SPI:
#define sclk 4
#define mosi 5
#define cs 6
#define dc 7
#define rst 8

where dc=A0, mosi=SDA

HW SPI:
//#define sclk 13
//#define mosi 11
#define cs 10
#define dc 9
#define rst 8

P.
PS: my module has got a BGR color coding..

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SOLVED - unable to make it work 1.8 SPI TFT 128x160

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