Microchip Technology dsPIC33 Reference Manual
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Microchip Technology dsPIC33 Reference Manual

Microchip Technology dsPIC33 Reference Manual

Liquid crystal display
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HIGHLIGHTS
This section of the manual contains the following major topics:
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0 LCD Waveform Generation............................................................................................. 22
11.0 LCD Interrupts................................................................................................................. 36
12.0 Configuring the LCD Module........................................................................................... 38
13.0 Operation During Sleep .................................................................................................. 39
14.0 Registers......................................................................................................................... 40
15.0 Revision History .............................................................................................................. 41
 2010-2013 Microchip Technology Inc.
Liquid Crystal Display (LCD)
Introduction ....................................................................................................................... 2
LCD Registers................................................................................................................... 3
LCD Segment Pins Configuration ..................................................................................... 6
LCD Clock Source Selection............................................................................................. 8
LCD Bias Types ................................................................................................................ 9
LCD Multiplex Types ....................................................................................................... 21
Segment Enables............................................................................................................ 22
Pixel Control.................................................................................................................... 22
LCD Frame Frequency ................................................................................................... 22

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Summary of Contents for Microchip Technology dsPIC33

  • Page 1: Table Of Contents

    LCD Frame Frequency ....................22 10.0 LCD Waveform Generation..................... 22 11.0 LCD Interrupts......................... 36 12.0 Configuring the LCD Module................... 38 13.0 Operation During Sleep ....................39 14.0 Registers......................... 40 15.0 Revision History ......................41  2010-2013 Microchip Technology Inc. DS30009740B-page 1...

  • Page 2: Introduction

    Family Reference Manual INTRODUCTION The Liquid Crystal Display (LCD) driver module generates the timing control to drive a Static or Multiplexed LCD panel. In the 100-pin devices (PIC24FJXXXGA3XX), the module drives panels of up to eight commons and up to 60 segments when 5 to 8 commons are used, and up to 64 segments when 1 to 4 commons are used.

  • Page 3: Lcd Registers

    2-2, configures the LCD clock source prescaler and the type of waveform: Type-A or Type-B. For details on these features, see Section 4.0 “LCD Clock Table 14-1 Source Selection”, Section 10.0 “LCD Waveform Generation”.  2010-2013 Microchip Technology Inc. DS30009740B-page 3...
  • Page 4 Family Reference Manual Register 2-1: LCDCON: LCD Control Register R/W-0 R/W-0 LCDEN — LCDSIDL — — — — — bit 15 bit 8 R/W-0 R/C-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 — SLPEN WERR LMUX2 LMUX1 LMUX0 bit 7 bit 0...
  • Page 5 1010 = 1:11 1001 = 1:10 1000 = 1:9 0111 = 1:8 0110 = 1:7 0101 = 1:6 0100 = 1:5 0011 = 1:4 0010 = 1:3 0001 = 1:2 0000 = 1:1  2010-2013 Microchip Technology Inc. DS30009740B-page 5...

  • Page 6: Lcd Segment Pins Configuration

    Family Reference Manual LCD SEGMENT PINS CONFIGURATION The LCDSEx registers configure the functions of the port pins. Setting the segment enable bit for a particular segment configures that pin as an LCD driver. There are four LCD Segment Enable...

  • Page 7: Ds30009740B-Page

    S48C3:S63C3 LCDDATA16 LCDDATA17 LCDDATA18 LCDDATA19 S00C4:S15C4 S16C4:S31C4 S32C4:S47C4 S48C4:S59C4 LCDDATA20 LCDDATA21 LCDDATA22 LCDDATA23 S00C5:S15C5 S16C5:S31C5 S32C5:S47C5 S48C5:S69C5 LCDDATA24 LCDDATA25 LCDDATA26 LCDDATA27 S00C6:S15C6 S16C6:S31C6 S32C6:S47C6 S48C6:S59C6 LCDDATA28 LCDDATA29 LCDDATA30 LCDDATA31 S00C7:S15C7 S16C7:S31C7 S32C7:S47C7 S48C7:S59C7  2010-2013 Microchip Technology Inc. DS30009740B-page 7...

  • Page 8: Lcd Clock Source Selection

    Family Reference Manual LCD CLOCK SOURCE SELECTION The LCD driver module has three possible clock sources: • FRC/8192 • SOSC Clock/32 • LPRC/32 The first clock source is the 8 MHz Fast Internal RC (FRC) oscillator, divided by 8,192. This divider ratio is chosen to provide about 1 kHz output.

  • Page 9: Lcd Bias Types

    (using LCDCST<2:0>). Table 5-1: Internal Resistance Ladder Power Modes Nominal Power Mode Resistance of Entire Ladder 3 MΩ 1 µA Medium 300 kΩ 10 µA High 30 kΩ 100 µA  2010-2013 Microchip Technology Inc. DS30009740B-page 9...
  • Page 10 Family Reference Manual Figure 5-1: LCD Bias Internal Resistor Ladder Connection Diagram LCDIRE LCDCST<2:0> VLCD3PE LCDBIAS3 VLCD2PE LCDBIAS2 VLCD1PE LCDBIAS1 Medium High Resistor Resistor Resistor Ladder Ladder Ladder A Power Mode B Power Mode LRLAT<2:0> LRLAP<1:0> LRLBP<1:0> There are two power modes, designated as “Mode A” and “Mode B”. Mode A is set by the bits, LRLAP<1:0>, and Mode B by the LRLBP<1:0>...
  • Page 11 Single Segment Time lcd_32x_clk ‘H00 ‘H01 ‘H02 ‘H03 ‘H04 ‘H05 ‘H06 ‘H07 ‘H1E ‘H1F ‘H00 ‘H01 cnt<4:0> lcd_clk LRLAT<2:0> ‘H3 Segment Data LRLAT<2:0> Power Mode Power Mode A Power Mode B Mode A  2010-2013 Microchip Technology Inc. DS30009740B-page 11...
  • Page 12 Family Reference Manual 5.1.2 CONTRAST CONTROL The LCD contrast control circuit consists of a 7-tap resistor ladder, controlled by the LCDCST<2:0> bits (see Figure 5-3). Figure 5-3: Internal Reference and Contrast Control Block Diagram 7 Stages Analog To Top of Reference Ladder LCDCST<2:0>...
  • Page 13 10 = Internal LCD reference ladder is powered in Medium Power mode 01 = Internal LCD reference ladder is powered in Low-Power mode 00 = Internal LCD reference ladder is powered down and unconnected bit 3 Unimplemented: Read as ‘0’  2010-2013 Microchip Technology Inc. DS30009740B-page 13...
  • Page 14 Family Reference Manual Register 5-1: LCDREF: LCD Reference Ladder Control Register (Continued) bit 2-0 LRLAT<2:0>: LCD Reference Ladder A Time Interval Control bits Sets the number of 32 clock counts when the A Time Interval Power mode is active.
  • Page 15 0 = Regulator output supports Static LCD Bias mode bit 1-0 CKSEL<1:0>: Regulator Clock Source Select bits 11 = 31 kHz LPRC 10 = 8 MHz FRC 01 = SOSC 00 = LCD regulator is disabled  2010-2013 Microchip Technology Inc. DS30009740B-page 15...
  • Page 16 Family Reference Manual Bias Configurations dsPIC33/PIC24 family devices have four distinct circuit configurations for LCD Bias generation: • M0: Regulator with Boost • M1: Regulator without Boost • M2: Resistor Ladder with Software Contrast • M3: Resistor Ladder with Hardware Contrast 5.3.1...
  • Page 17 3.6V) Mode 1 (V BIAS BIAS These values are provided for design guidance only. They should be optimized for the application by the designer Note 1: based on the actual LCD specifications.  2010-2013 Microchip Technology Inc. DS30009740B-page 17...
  • Page 18 Family Reference Manual 5.3.3 M2 (RESISTOR LADDER WITH SOFTWARE CONTRAST) M2 operation also uses the LCD regulator but disables the charge pump. The regulator’s internal voltage reference remains active as a way to regulate contrast. It is used in cases where the current requirements of the LCD exceed the capacity of the regulator’s charge pump.
  • Page 19 These values are provided for design guidance only. They should be optimized for the application by the Note 1: designer based on the actual LCD specifications. A potentiometer for manual contrast adjustment is optional; it may be omitted entirely.  2010-2013 Microchip Technology Inc. DS30009740B-page 19...
  • Page 20 Family Reference Manual Design Considerations for the LCD Charge Pump When designing applications that use the LCD regulator with the charge pump enabled, users must always consider both the dynamic current and RMS (Static) current requirements of the dis- play, and what the charge pump can deliver.

  • Page 21: Lcd Multiplex Types

    Pins, COM<7:4>, can also be used as SEG pins when 1/4 Multiplex to Static Multiplex are used. These Note: pins can be used as I/O pins only if the respective bits in the LCDSEx registers are set to ‘0’.  2010-2013 Microchip Technology Inc. DS30009740B-page 21...

  • Page 22: Segment Enables

    Family Reference Manual SEGMENT ENABLES The LCDSEx registers are used to select the pin function for each segment pin. The selection allows each pin to operate as either an LCD segment driver or a digital only pin. To configure the pin as a segment driver, the corresponding bits in the LCDSEx registers must be set to ‘1’.
  • Page 23 Figure 10-13 provide waveforms for Static, Half-Multiplex, One-Third Multiplex and Quarter Multiplex drives for Type-A and Type-B waveforms. Figure 10-1: Type-A/Type-B Waveforms in Static Drive COM0 COM0 SEG0 SEG1 COM0-SEG0 COM0-SEG1 1 Frame  2010-2013 Microchip Technology Inc. DS30009740B-page 23...
  • Page 24 Family Reference Manual Figure 10-2: Type-A Waveforms in 1/2 MUX, 1/2 Bias Drive COM0 COM1 COM0 COM1 SEG0 SEG1 COM0-SEG0 COM0-SEG1 1 Frame  2010-2013 Microchip Technology Inc. DS30009740B-page 24...
  • Page 25 Liquid Crystal Display (LCD) Figure 10-3: Type-B Waveforms in 1/2 MUX, 1/2 Bias Drive COM0 COM1 COM0 COM1 SEG0 SEG1 COM0-SEG0 COM0-SEG1 2 Frames  2010-2013 Microchip Technology Inc. DS30009740B-page 25...
  • Page 26 Family Reference Manual Figure 10-4: Type-A Waveforms in 1/2 MUX, 1/3 Bias Drive COM0 COM1 COM0 COM1 SEG0 SEG1 COM0-SEG0 COM0-SEG1 1 Frame  2010-2013 Microchip Technology Inc. DS30009740B-page 26...
  • Page 27 Liquid Crystal Display (LCD) Figure 10-5: Type-B Waveforms in 1/2 MUX, 1/3 Bias Drive COM0 COM1 COM0 COM1 SEG0 SEG1 COM0-SEG0 COM0-SEG1 2 Frames  2010-2013 Microchip Technology Inc. DS30009740B-page 27...
  • Page 28 Family Reference Manual Figure 10-6: Type-A Waveforms in 1/3 MUX, 1/2 Bias Drive COM0 COM2 COM1 COM1 COM0 COM2 SEG0 SEG2 SEG1 COM0-SEG0 COM0-SEG1 1 Frame  2010-2013 Microchip Technology Inc. DS30009740B-page 28...
  • Page 29 Liquid Crystal Display (LCD) Figure 10-7: Type-B Waveforms in 1/3 MUX, 1/2 Bias Drive COM0 COM2 COM1 COM1 COM0 COM2 SEG0 SEG1 COM0-SEG0 COM0-SEG1 2 Frames  2010-2013 Microchip Technology Inc. DS30009740B-page 29...
  • Page 30 Family Reference Manual Figure 10-8: Type-A Waveforms in 1/3 MUX, 1/3 Bias Drive COM0 COM2 COM1 COM1 COM0 COM2 SEG0 SEG2 SEG1 COM0-SEG0 COM0-SEG1 1 Frame  2010-2013 Microchip Technology Inc. DS30009740B-page 30...
  • Page 31 Liquid Crystal Display (LCD) Figure 10-9: Type-B Waveforms in 1/3 MUX, 1/3 Bias Drive COM0 COM2 COM1 COM1 COM0 COM2 SEG0 SEG1 COM0-SEG0 COM0-SEG1 2 Frames  2010-2013 Microchip Technology Inc. DS30009740B-page 31...
  • Page 32 Family Reference Manual Figure 10-10: Type-A Waveforms in 1/4 MUX, 1/3 Bias Drive COM3 COM2 COM0 COM1 COM1 COM0 COM2 COM3 SEG0 SEG1 COM0-SEG0 COM0-SEG1 1 Frame  2010-2013 Microchip Technology Inc. DS30009740B-page 32...
  • Page 33 Liquid Crystal Display (LCD) Figure 10-11: Type-B Waveforms in 1/4 MUX, 1/3 Bias Drive COM3 COM2 COM0 COM1 COM1 COM0 COM2 COM3 SEG0 SEG1 COM0-SEG0 COM0-SEG1 2 Frames  2010-2013 Microchip Technology Inc. DS30009740B-page 33...
  • Page 34 Family Reference Manual Figure 10-12: Type-A Waveforms in 1/8 MUX, 1/3 Bias Drive COM4 COM0 COM3 COM5 COM7 COM1 COM6 COM2 COM1 COM0 COM2 COM7 SEG0 COM0-SEG0 COM1-SEG0  2010-2013 Microchip Technology Inc. DS30009740B-page 34...
  • Page 35 Liquid Crystal Display (LCD) Figure 10-13: Type-B Waveforms in 1/8 MUX, 1/3 Bias Drive COM4 COM0 COM3 COM5 COM7 COM6 COM2 COM1 COM1 COM0 COM2 COM7 SEG0 COM0 - SEG0 COM1 - SEG0  2010-2013 Microchip Technology Inc. DS30009740B-page 35...

  • Page 36: Lcd Interrupts

    Family Reference Manual 11.0 LCD INTERRUPTS The LCD timing generation provides an interrupt that defines the LCD frame timing. This interrupt can be used to coordinate the writing of the pixel data with the start of a new frame, which produces a visually crisp transition of the image.
  • Page 37 = (T /2 – (2 T /4) – (2 T + 40 ns) FINT FRAME + 40 ns)) Maximum = 1.5(T /2 – (1 T /4) – (1 T + 40 ns) FRAME  2010-2013 Microchip Technology Inc. DS30009740B-page 37...

  • Page 38: Configuring The Lcd Module

    Family Reference Manual 12.0 CONFIGURING THE LCD MODULE To configure the LCD module: Select the frame clock prescale using bits, LP<2:0> (LCDPS<2:0>). Configure the appropriate pins to function as segment drivers using the LCDSEx registers. If using the internal reference resistors for biasing, enable the internal reference ladder and: •...

  • Page 39: Operation During Sleep

    LCDDATAx registers. The LCD data cannot be changed. Figure 13-1: Sleep Entry/Exit when SLPEN = 1 or CS<1:0> = 00 COM0 COM1 COM2 SEG0 2 Frames SLEEP Instruction Execution Wake-up  2010-2013 Microchip Technology Inc. DS30009740B-page 39...

  • Page 40: Registers

    14.0 REGISTERS Table 14-1: Special Function Registers Associated with LCD Driver Module Name Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 LCDCON...

  • Page 41: Revision History

    Revision A (December 2010) This is the initial released revision of this document. Revision B (October 2013) Corrected CS<1:0> bit information in Register 2-1. Removed MUX from Figure 5-3. Minor typographical edits throughout document.  2010-2013 Microchip Technology Inc. DS30009740B-page 41...
  • Page 42 Family Reference Manual NOTES:  2010-2013 Microchip Technology Inc. DS30009740B-page 42...
  • Page 43 Total Endurance, TSHARC, UniWinDriver, WiperLock, ZENA and Z-Scale are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. GestIC and ULPP are registered trademarks of Microchip Technology Germany II GmbH &...
  • Page 44 Tel: 66-2-694-1351 China - Xian Tel: 86-29-8833-7252 Fax: 66-2-694-1350 Toronto Fax: 86-29-8833-7256 Mississauga, Ontario, Canada China - Xiamen Tel: 905-673-0699 Tel: 86-592-2388138 Fax: 905-673-6509 Fax: 86-592-2388130 China - Zhuhai Tel: 86-756-3210040 08/20/13 Fax: 86-756-3210049  2010-2013 Microchip Technology Inc. DS30009740B-page 44...

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