SLAA654A November   2014  – July 2015 CC430F6147 , MSP430F412 , MSP430F413 , MSP430F4132 , MSP430F415 , MSP430F4152 , MSP430F417 , MSP430F423A , MSP430F4250 , MSP430F425A , MSP430F4260 , MSP430F4270 , MSP430F427A , MSP430F435 , MSP430F4351 , MSP430F436 , MSP430F4361 , MSP430F437 , MSP430F4371 , MSP430F438 , MSP430F439 , MSP430F447 , MSP430F448 , MSP430F4481 , MSP430F449 , MSP430F4491 , MSP430F4616 , MSP430F46161 , MSP430F4617 , MSP430F46171 , MSP430F4618 , MSP430F46181 , MSP430F4619 , MSP430F46191 , MSP430F47126 , MSP430F47127 , MSP430F47163 , MSP430F47166 , MSP430F47167 , MSP430F47173 , MSP430F47176 , MSP430F47177 , MSP430F47183 , MSP430F47186 , MSP430F47187 , MSP430F47193 , MSP430F47196 , MSP430F47197 , MSP430F477 , MSP430F478 , MSP430F4783 , MSP430F4784 , MSP430F479 , MSP430F4793 , MSP430F4794 , MSP430F6433 , MSP430F6435 , MSP430F6436 , MSP430F6438 , MSP430F6458 , MSP430F6459 , MSP430F6630 , MSP430F6631 , MSP430F6632 , MSP430F6633 , MSP430F6634 , MSP430F6635 , MSP430F6636 , MSP430F6637 , MSP430F6638 , MSP430F6658 , MSP430F6659 , MSP430F6720 , MSP430F6720A , MSP430F6721 , MSP430F6721A , MSP430F6723 , MSP430F6723A , MSP430F6724 , MSP430F6724A , MSP430F6725 , MSP430F6725A , MSP430F6726 , MSP430F6726A , MSP430F6730 , MSP430F6730A , MSP430F6731 , MSP430F6731A , MSP430F6733 , MSP430F6733A , MSP430F6734 , MSP430F6734A , MSP430F6735 , MSP430F6735A , MSP430F6736 , MSP430F6736A , MSP430F6745 , MSP430F67451 , MSP430F67451A , MSP430F6745A , MSP430F6746 , MSP430F67461 , MSP430F67461A , MSP430F6746A , MSP430F6747 , MSP430F67471 , MSP430F67471A , MSP430F6747A , MSP430F6748 , MSP430F67481 , MSP430F67481A , MSP430F6748A , MSP430F6749 , MSP430F67491 , MSP430F67491A , MSP430F6749A , MSP430F67621 , MSP430F67621A , MSP430F67641 , MSP430F67641A , MSP430F6765 , MSP430F67651 , MSP430F67651A , MSP430F6765A , MSP430F6766 , MSP430F67661 , MSP430F67661A , MSP430F6766A , MSP430F6767 , MSP430F67671 , MSP430F67671A , MSP430F6767A , MSP430F6768 , MSP430F67681 , MSP430F67681A , MSP430F6768A , MSP430F6769 , MSP430F67691 , MSP430F67691A , MSP430F6769A , MSP430F6775 , MSP430F67751 , MSP430F67751A , MSP430F6775A , MSP430F6776 , MSP430F67761 , MSP430F67761A , MSP430F6776A , MSP430F6777 , MSP430F67771 , MSP430F67771A , MSP430F6777A , MSP430F6778 , MSP430F67781 , MSP430F67781A , MSP430F6778A , MSP430F6779 , MSP430F67791 , MSP430F67791A , MSP430F6779A , MSP430FE423 , MSP430FE4232 , MSP430FE423A , MSP430FE4242 , MSP430FE425 , MSP430FE4252 , MSP430FE425A , MSP430FE427 , MSP430FE4272 , MSP430FE427A , MSP430FG4250 , MSP430FG4260 , MSP430FG4270 , MSP430FG437 , MSP430FG438 , MSP430FG439 , MSP430FG4616 , MSP430FG4617 , MSP430FG4618 , MSP430FG4619 , MSP430FG477 , MSP430FG478 , MSP430FG479 , MSP430FG6425 , MSP430FG6426 , MSP430FG6625 , MSP430FG6626 , MSP430FR4131 , MSP430FR4132 , MSP430FR4133 , MSP430FR5870 , MSP430FR5872 , MSP430FR58721 , MSP430FR5922 , MSP430FR59221 , MSP430FR5970 , MSP430FR5972 , MSP430FR59721 , MSP430FR6820 , MSP430FR6822 , MSP430FR68221 , MSP430FR6870 , MSP430FR6872 , MSP430FR68721 , MSP430FR6877 , MSP430FR6879 , MSP430FR68791 , MSP430FR6887 , MSP430FR6888 , MSP430FR6889 , MSP430FR68891 , MSP430FR6920 , MSP430FR6922 , MSP430FR69221 , MSP430FR6927 , MSP430FR69271 , MSP430FR6928 , MSP430FR6970 , MSP430FR6972 , MSP430FR69721 , MSP430FR6977 , MSP430FR6979 , MSP430FR69791 , MSP430FR6987 , MSP430FR6988 , MSP430FR6989 , MSP430FR69891 , MSP430FW423 , MSP430FW425 , MSP430FW427 , MSP430FW428 , MSP430FW429

 

  1.   Designing With MSP430™ MCUs and Segment LCDs
    1.     Trademarks
    2. 1 Introduction: MSP430 + LCD End Applications
    3. 2 MSP430 LCD Portfolio
    4. 3 Segmented LCD Operation
      1. 3.1 LCD Structure (Simplified)
      2. 3.2 LCD Drive Basics
    5. 4 MSP430 LCD Features
      1. 4.1  Muxing
        1. 4.1.1 Muxing Example
      2. 4.2  Charge Pump
      3. 4.3  Biasing
      4. 4.4  Contrast Control
      5. 4.5  Timing
      6. 4.6  Memory Map
      7. 4.7  Blinking
      8. 4.8  LCD Output Pins
      9. 4.9  Ultra-Low-Power Features
      10. 4.10 Driving Large LCDs
    6. 5 LCD Layout and Software Considerations
      1. 5.1 LCD Layout Tips
        1. 5.1.1 Hardware-Driven Layout
        2. 5.1.2 Software-Driven Layout
        3. 5.1.3 General Layout Rules
      2. 5.2 LCD Software Tips
        1. 5.2.1 Create a Lookup Table
        2. 5.2.2 Use of #defines
        3. 5.2.3 Efficient Clearing of the LCD Memory
        4. 5.2.4 Double-Buffering of the Display Buffer Using Dual Display Memory
        5. 5.2.5 Efficient Binary-to-BCD Conversion
    7. 6 Devices Without LCD Module
      1. 6.1 Bit-Banged LCD
        1. 6.1.1 Bit-Banged LCD Tradeoffs
      2. 6.2 Displays With Built-in Drivers and Serial Interface
    8. 7 Additional Resources
  2.   Revision History

4.1 Muxing

Segmented LCDs use multiplexing (muxing) to limit control pin count. Types of displays include static (no muxing), 2-mux, 3-mux, 4-mux, etc. – even up to 8-mux. The notation N-mux means each segment pin Sx drives N segments on the display – this also means there are N common (COMx) pins. Each LCD segment on the display is driven by the combination of a COMx pin and Sx pin, providing a difference in potential across the liquid crystals for that segment.

Muxing allows a much larger number of segments to be controlled by a limited number of pins. If for example there is an 8-mux LCD display, then there are 8 COM pins and each segment (Sx) pin can drive 8 segments. So for example when using an 8-mux capable MSP430 with 40 Sx pins available (S0-S39), then it could control 320 segments with only 8 (COMx) + 40 (Sx) = 48 pins.

Some MSP430 devices with 8-mux mode can support up to 320 segment displays. However, always make sure to check the device-specific data sheet to see how many segments the particular device supports, as it is limited not only by the muxing capability of the LCD module but also by the number of LCD pins available on the particular device in a particular pin-package.

fig03_4mux_connections.pngFigure 3. 4-Mux Connections and Waveforms