OM13082 LCD12864 backlight

[john_schooling]

OM13082 (https://www.nxp.com/support/developer-resources/evaluation-and-development-boards/lpcxpresso-boards/...)

has an LCD12864.

I can't believe there is no backlight.  Have I missed something?

[john_schooling]

Hi XiangJun,

The pins in your document do not match the display ribbon or the circuit diagram on the OM13082 board.

There is no evidence of LEDA/LEDK on the OM13082 board connector.  There are 20 pins on the LCD and 28 pins on the external end of the ribbon cable.  The unused 8 pins are connected to capacitors on the OM13082 board (presumably for a different LCD display).

Here are the pins:

LCD12864 ribbon FPC-WKG12864...
ST7565S controller
                                      OM13082      OM13082
LCD side    external connector        connector    CCT
========    =======================   =========    =======
 1  CS        1                       CS           R8  -> CS
 2  /RES      2                       RST                 nRST
 3  CD        3                       C/D          R11 -> CD
 4            4                       WR   (NC)    
 5            5                       RD   (NC)    
 6  D0        6                       D0   (NC)    
 7  D1        7                       D1   (NC)    
 8  D2        8                       D2   (NC)    
 9  D3        9                       D3   (NC)    
10  D4       10                       D4   (NC)    
11  D5       11                       D5   (NC)    
12  D6(SCL)  12                       D6/SCK       SCLK
13  D7(SI)   13 1 - 13 = thin wires   D7/SID       MOSI
14  VSS      14 Thick wire            VSS          GND
17  VOUT     15                       VOUT         C20 -> GND
             16 NC                    CAP3P        C14
             17 NC                    CAP1N        C14/C18
             18 NC                    CAP1P        C18
15           19                       CAP2P        C19
16           20                       CAP2N        C19
             21 NC                    V4           C13 -> VDD
             22 NC                    V3           C12 -> VDD
             23 NC                    V2           C11 -> VDD
             24 NC                    V1           C10 -> VDD
             25 NC                    V0           C9  -> VDD
18  C86      26                       L:C86/H:C68  VDD        MPU interface.  H = 6800 series.  L = 8080.
19  P/S      27                       L:S/H:P      GND        L = serial (SCL/SI)
20           28 Thick wire VDD        VDD          VDD

Thanks.

John.

[xiangjun_rong]

Hi, John,

Thanks, I see.

BR

Xiangjun Rong

[xiangjun_rong]

Hi, John,

The OM13082 board uses LCD12864 as liquid screen, the LCD12864 liquid screen has the backlight pins exactly. The Pin 19 is LEDA pin(it should connect +5V of backlight) , the pin 20 is LEDK pin(it should connect to GND, the GND of back light).

This is the data sheet of LCD12864, but it is written with Chinese.

http://www.dfrobot.com.cn/image/data/FIT0021/CN/LCD12864%20chinese%20char.pdf 

Regarding the board, I think the LEDA/LEDK should be connected to +5V rather than a capacitor.

BR

XiangJun Rong