• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 30 subscribers
  • Views 1491 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LCD driver NT75451 issue using SPI interface

Caleg
Prodigy 90 points

Hi there

I'm trying to interface my Cortex M (Stellaris launchpad) to a small display that uses the NT75451 SPI interface.

However, I'm stuck with it because the display remains black.

As a base project I used the glcd library (http://agock.com/software/glcd-graphic-lcd-library/). This library has an implementation to the NT75451 with a parallel interface.

At init I setup the display with the sequence below; however, I'm not sure at all about it since my display has a very poor documentation...

Any idea what the problem could be? Wrong initialization?

Thanks for your help

----

GLCD_RESET_LOW();  // Display RESET line low
delay_ms(GLCD_RESET_TIME); // 1 ms delay
GLCD_RESET_HIGH();
glcd_command(0xE2); /* S/W RESET OK */
glcd_command(0xA2); /* LCD bias OK */
glcd_command(0xA0); /* ADC select OK */
glcd_command(0xC0); /* SHL Normal ?? */
// glcd_command(0x81); /* Ref vg select mode */
glcd_command(0x2F); /* Power control ?? */
glcd_command(0x22); /* reg resistor select ?? */
// glcd_command(0x8F); /* Ref vg select mode */
glcd_command(0xAF); /* Display ON */

The glcd_command() function correspond to a spi_write() with the A0 line low

-----

  • 0
    Intellectual 965 points

    Hi,

    You can use the following commands to initialise 

    glcd_write_cmd(par, 0xE2); /* S/W RESWT */
    glcd_write_cmd(par, 0xA0); /* ADC select */
    glcd_write_cmd(par, 0xC8); /* SHL Normal */
    glcd_write_cmd(par, 0xA3); /* LCD bias */
    glcd_write_cmd(par, 0x2F); /* Power control */
    glcd_write_cmd(par, 0x22); /* reg resistor select */
    glcd_write_cmd(par, 0x40); /* Initial display line 40 */
    glcd_write_cmd(par, 0xA4); /* Normal display a4 */
    glcd_write_cmd(par, 0xA6); /* Reverce display a7 */
    glcd_write_cmd(par, 0x81); /* Ref vg select mode */
    glcd_write_cmd(par, 0x3f); /* Ref vg reg select */
    glcd_write_cmd(par, 0xB0); /* Set page address */
    glcd_write_cmd(par, 0x10); /* Set coloumn addr MSB */
    glcd_write_cmd(par, 0x00); /* Set coloumn addr LSB */
    glcd_write_cmd(par, 0xAF); /* Display ON */

    Make A0 line high for writing data and make it low for writing commamd 

    Thanks

  • 0 in reply to Shinu Mary Varghese
    Prodigy 90 points

    Hmmm...

    The display is still black... I need to check the HW again ...

    Thanks!