Hello,
We have bunch of 1.8" TFT displays from multiple vendors.
Some are shiny and bright, but some are quite dim.
These are "no-name" displays are from multiple vendors without exact datasheets.
I am trying to figure out if I can do something to increase brightness for these dim panels so we can use them in prototypes and demo's.
I have more than 100 of these.
My first attempt was to increase backlight current, but even with 30mA (20mA nominal) these are not bright enough.
So I am thinking if these may need a different INIT values that we should be using.
Without displays datasheets, I can use only ST7735 information, but I am not sure what to change, so I am looking for ideas.
We power them from about 3.4V (both LCD and PIC)
Below is my current INIT code, credit to Adafruit libraries, but I am using it with a PIC microcontrollers.
Thank you in advance.
We have bunch of 1.8" TFT displays from multiple vendors.
Some are shiny and bright, but some are quite dim.
These are "no-name" displays are from multiple vendors without exact datasheets.
I am trying to figure out if I can do something to increase brightness for these dim panels so we can use them in prototypes and demo's.
I have more than 100 of these.
My first attempt was to increase backlight current, but even with 30mA (20mA nominal) these are not bright enough.
So I am thinking if these may need a different INIT values that we should be using.
Without displays datasheets, I can use only ST7735 information, but I am not sure what to change, so I am looking for ideas.
We power them from about 3.4V (both LCD and PIC)
Below is my current INIT code, credit to Adafruit libraries, but I am using it with a PIC microcontrollers.
Thank you in advance.
Code:
ST7735_SWRESET, DELAY, // 1: Software reset cmd1, 0 args, w/delay
150, // 150 ms delay
ST7735_SLPOUT , DELAY, // 2: Out of sleep mode, 0 args, w/delay
255, // 500 ms delay
ST7735_FRMCTR1, 3 , // 3: Frame rate ctrl - normal mode, 3 args:
0x01, 0x2C, 0x2D, // Rate = fosc/(1x2+40) * (LINE+2C+2D)
ST7735_FRMCTR2, 3 , // 4: Frame rate control - idle mode, 3 args:
0x01, 0x2C, 0x2D, // Rate = fosc/(1x2+40) * (LINE+2C+2D)
ST7735_FRMCTR3, 6 , // 5: Frame rate ctrl - partial mode, 6 args:
0x01, 0x2C, 0x2D, // Dot inversion mode
0x01, 0x2C, 0x2D, // Line inversion mode
ST7735_INVCTR , 1 , // 6: Display inversion ctrl, 1 arg, no delay:
0x07, // No inversion
ST7735_PWCTR1 , 3 , // 7: Power control, 3 args, no delay:
0xA2,
0x02, // -4.6V
0x84, // AUTO mode
ST7735_PWCTR2 , 1 , // 8: Power control, 1 arg, no delay:
0xC5, // VGH25 = 2.4C VGSEL = -10 VGH = 3 * AVDD
ST7735_PWCTR3 , 2 , // 9: Power control, 2 args, no delay:
0x0A, // Opamp current small
0x00, // Boost frequency
ST7735_PWCTR4 , 2 , // 10: Power control, 2 args, no delay:
0x8A, // BCLK/2, Opamp current small & Medium low
0x2A,
ST7735_PWCTR5 , 2 , // 11: Power control, 2 args, no delay:
0x8A, 0xEE,
ST7735_VMCTR1 , 1 , // 12: Power control, 1 arg, no delay:
0x0E,
ST7735_INVOFF , 0 , // 13: Don't invert display, no args, no delay
ST7735_MADCTL , 1 , // 14: Memory access control (directions), 1 arg:
0xC0, // row addr/col addr, bottom to top refresh
ST7735_COLMOD , 1 , // 15: set color mode, 1 arg, no delay:
0x05 }, // 16-bit color
ST7735_CASET , 4 , // 1: Column addr set, 4 args, no delay:
0x00, 0x00, // XSTART = 0
0x00, 0x7F, // XEND = 127
ST7735_RASET , 4 , // 2: Row addr set, 4 args, no delay:
0x00, 0x00, // XSTART = 0
0x00, 0x9F, // XEND = 159
ST7735_GMCTRP1, 16 , // 1: Command 0xE0, Gamma 16 args, no delay:
0x02, 0x1c, 0x07, 0x12,
0x37, 0x32, 0x29, 0x2d,
0x29, 0x25, 0x2B, 0x39,
0x00, 0x01, 0x03, 0x10,
ST7735_GMCTRN1, 16 , // 2: Command 0xE1, Gamma 16 args, no delay:
0x03, 0x1d, 0x07, 0x06,
0x2E, 0x2C, 0x29, 0x2D,
0x2E, 0x2E, 0x37, 0x3F,
0x00, 0x00, 0x02, 0x10,
ST7735_NORON , DELAY, // 3: Normal display on, no args, w/delay
10, // 10 ms delay
ST7735_DISPON , DELAY, // 4: Main screen turn on, no args w/delay
100 // 100 ms delay
