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LCD Driver

LCD Viewing angle for 8 COM vs 4 COM

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I’m planning to make a custom LCD made. The LCD has 128 segments. Now, in order to drive it, I have two options :

  • Use 4 COM + 32 pins
  • Use 8 COM + 16 pins

The MCU which I’m looking at (STM8L052R8) has support for 4 COM x 28 (112) or 8 COM x 24 (192). Since I have 128 segments, If I choose this MCU, then I’ll need to go for 8COM config (8×16 = 128).

Many vendors have flatly told me that the viewing would not be good, and given me advice that 4COM would be better to view. Since I’ve little idea what they mean, I need better understanding of why this is so. And how bad would this viewing angle be, apart from other issues which I dont know of if 8 COM is used.

My expectation is its okay if the LCD has to be viewed in a 45 degree range.lcdpinsshareedit  follow  flag asked 3 hours agoOuroboros17755 bronze badges

  • I don’t understand what you you mean by “LCD made”. Do you mean 32″, LCD TV monitor, or 7″ HDMI LCD monitor, or 640 x 480 64k color graphics display, or 16 char x 2 line LCD monochrome display, each character is 5 dots by 7 dots? Do you have any particular LCD driver in mind, or do you hope to directly drive the LCD using STM8L0528? As I know the viewing angle is a characteristic of the hardware display, not programmable by software. I admit that I only know how to drive 640 x 480 graphics display and 20 char x 4 lines LCD display. I would be grateful if you can upgrade my LCD knowledge. – tlfong01 2 hours ago   
  • 1@tlfong01 It is clearly about segmented LCD. – Chupacabras 1 hour ago
  • @Chupacabras, thanks a lot for your guidance. I am a electronics hobbyist and have never heard about “segmented LCD“. I must google to know more. Cheers. – tlfong01 36 mins ago   
  • @Chupacabras, do you mean those 7-segment character displays? The segment drivers I have been playing is called MAX7219. I used it to display 7 and 16 segments characters, and also scalable 8 x 8 dot matrix LED displays. They are dirt cheap and good for newbies to learn matrix displays. / to continue, … – tlfong01 16 mins ago   
  • @Chupacabras (1) MAX7219 Lattice Modules 4-in-One Tube Digital Display Module 8×8 Common Cathode Single Chip Module US$1 – US$4 es.aliexpress.com/item/… (2) SPI MAX7219 Serially Interfaced, 8-Digit, LED Display Drivers – Maxim maximintegrated.com/en/products/power/display-power-control/…. / to continued, .. – tlfong01 15 mins ago    
  • @Chupacabras, There are many MAX7219 demo Arduino programs around. I found it easy to direct program in Rpi python. I think they are good for newbies to learn SPI. But I don’t understand why the OP mentions 45 degree veiwing angle and 4COM and 8 COM. Perhaps I need to google harder. – tlfong01 8 mins ago   
  • @Chupacabras, I also played with LCD drivers, but they are tedious to program, using 4 or 8 GPIO pins Fortunately now there are I2C interface LCD modules which are easy to interface. (3) HD44780 LCD Driver – Hitachi en.wikipedia.org/wiki/Hitachi_HD44780_LCD_controller (4) LCD Fundamentals and the LCD Driver Module of 8-Bit PIC Microcontrollers – App Notes AN658, MicroChip ww1.microchip.com/downloads/en/Appnotes/…. Cheers. – tlfong01 just now   Edit   

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