ZHCSBP5C september   2013  – october 2020 SN65DSI86

PRODUCTION DATA  

  1.   1
  2. 特性
  3. 应用
  4. 说明
  5. Revision History
  6. Description (continued)
  7. Pin Configuration and Functions
  8. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Switching Characteristics
  9. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 MIPI Dual DSI Interface
      2. 8.3.2 Embedded DisplayPort Interface
      3. 8.3.3 General-Purpose Input and Outputs
        1. 8.3.3.1 GPIO REFCLK and DSIA Clock Selection
        2. 8.3.3.2 Suspend Mode
        3. 8.3.3.3 Pulse Width Modulation (PWM)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Reset Implementation
      2. 8.4.2 Power-Up Sequence
      3. 8.4.3 Power Down Sequence
      4. 8.4.4 Display Serial Interface (DSI)
        1. 8.4.4.1 DSI Lane Merging
        2. 8.4.4.2 DSI Supported Data Types
        3. 8.4.4.3 Generic Request Datatypes
          1. 8.4.4.3.1 Generic Read Request 2-Parameters Request
          2. 8.4.4.3.2 Generic Short Write 2-Parameters Request
          3. 8.4.4.3.3 Generic Long Write Packet Request
        4. 8.4.4.4 DSI Pixel Stream Packets
        5. 8.4.4.5 DSI Video Transmission Specifications
        6. 8.4.4.6 Video Format Parameters
        7. 8.4.4.7 GPU LP-TX Clock Requirements
      5. 8.4.5 DisplayPort
        1. 8.4.5.1  HPD (Hot Plug/Unplug Detection)
        2. 8.4.5.2  AUX_CH
          1. 8.4.5.2.1 Native Aux Transactions
        3. 8.4.5.3  I2C-Over-AUX
          1. 8.4.5.3.1 Direct Method (Clock Stretching)
          2. 8.4.5.3.2 Indirect Method (CFR Read/Write)
        4. 8.4.5.4  DisplayPort PLL
        5. 8.4.5.5  DP Output VOD and Pre-emphasis Settings
        6. 8.4.5.6  DP Main Link Configurability
        7. 8.4.5.7  DP Main Link Training
          1. 8.4.5.7.1 Manual Link Training
          2. 8.4.5.7.2 Fast Link Training
          3. 8.4.5.7.3 54
          4. 8.4.5.7.4 Semi-Auto Link Training
          5. 8.4.5.7.5 Redriver Semi-Auto Link Training
        8. 8.4.5.8  Panel Size vs DP Configuration
        9. 8.4.5.9  Panel Self Refresh (PSR)
        10. 8.4.5.10 Secondary Data Packet (SDP)
        11. 8.4.5.11 Color Bar Generator
        12. 8.4.5.12 DP Pattern
          1. 8.4.5.12.1 HBR2 Compliance Eye
          2. 8.4.5.12.2 80-Bit Custom Pattern
        13. 8.4.5.13 BPP Conversion
    5. 8.5 Programming
      1. 8.5.1 Local I2C Interface Overview
    6. 8.6 Register Map
      1. 8.6.1 Standard CFR Registers (PAGE 0)
  10. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 1080p (1920x1080 60 Hz) Panel
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 eDP Design Procedure
          2. 9.2.1.2.2 76
          3. 9.2.1.2.3 DSI Design Procedure
          4. 9.2.1.2.4 78
          5. 9.2.1.2.5 Example Script
        3. 9.2.1.3 Application Curve
  11. 10Power Supply Recommendations
    1. 10.1 VCC Power Supply
    2. 10.2 VCCA Power supply
    3. 10.3 VPLL and VCCIO Power Supplies
  12. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 DSI Guidelines
      2. 11.1.2 eDP Guidelines
      3. 11.1.3 Ground
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
  14. 13Mechanical, Packaging, and Orderable Information

Pulse Width Modulation (PWM)

The SN65DSI86 supports controlling the brightness of eDP display via pulse width modulation. The PWM signal is output over GPIO4 when GPIO4 control register is configured for PWM. For the SN65DSI86, the brightness is controlled by the BACKLIGHT register.

The granularity of brightness is controlled directly by the 16-bit BACKLIGHT_SCALE register. This register allows a granularity of up to 65535 increments. This register, in combination with either the BACKLIGHT register, will determine the duty cycle of the PWM. For example, if the BACKLIGHT_SCALE register is programmed to 0xFF and the BACKLIGHT is programmed to 0x40, then the duty cycle will be 25% (25% of the PWM period will be high and 75% of the PWM period will be low). The duty cycle would be 100% (PWM always HIGH) if the BACKLIGHT register was programmed to 0xFF and would be 0% (PWM always low) if BACKLIGHT register was programmed to 0x00. The BACKLIGHT_SCALE should be set equal to the digital value corresponding to the maximum possible backlight brightness that the display can produce. For example, if the backlight level is 16-bit, then BACKLIGHT_SCALE should be 0xFFFF, if it is an 8-bit range, then BACKLIGHT_SCALE should be set to 0x00FF.

Duty Cycle (high pulse) = (BACKLIGHT ) / (BACKLIGHT_SCALE +1)

The frequency of the PWM is determined by the REFCLK_FREQ register and the value programmed into both the PWM_PRE_DIV and BACKLIGHT_SCALE registers. The equation below determines the PWM frequency:

PWM FREQ = REFCLK_FREQ / (PWM_PRE_DIV × BACKLIGHT_SCALE + 1)

Regardless of the state of the DPPLL_CLK_SRC register, the REFCLK_FREQ value in above equation will be based on the frequencies of DPPLL_CLK_SRC equal 0 (12 MHz, 19.2 MHz, 26 MHz, 27 MHz, 38.4 MHz). The REFCLK_FREQ will not be the DSIA CLK frequency in the case where DPPLL_CLK_SRC equals one.

Note:

REFCLK or DACP/N must be running if GPIO4 is configured for PWM.