DLPU103B october   2020  – may 2023 DLP230NP

 

  1.   1
  2.   DLP LightCrafter Display 230NP EVM
  3.   Trademarks
  4. 1  DLP LightCrafter Display 230NP EVM Overview
  5. 2 Safety Instructions
  6. 3 Applicable Documents
  7. 4 What is in the DLP LightCrafter Display 230NP EVM?
  8. 5 Light Engine
  9. 6 Quick-Start Procedure
  10. 7 Connectors on Formatter Board
  11. 8 EVM Setup
  12. 9 Raspberry Pi Guide
    1. 9.1 Raspberry Pi General Configuration
    2. 9.2 Video Timing Configuration
    3. 9.3 Python Support Software
    4. 9.4 Operating Modes
    5. 9.5 Example Applications
      1. 9.5.1 Initialize Communication Between Raspberry Pi and EVM
      2. 9.5.2 Play Video Content from Raspberry Pi
      3. 9.5.3 Execute Sample Scripts Using Raspberry Pi
      4. 9.5.4 Rewrite Controller or FPGA Flash Device Using Raspberry Pi
  13. 10Troubleshooting
  14. 11Support Resources
  15. 12Revision History

9.2 Video Timing Configuration

The Raspberry Pi supports customizable video timing configurations over its DPI video output, as the configuration file (config.txt) in the "hdmi_timings" setting shows. To achieve the highest quality video output via this interface, TI recommends modifying the video timings provided based on the particular system use case for the Raspberry Pi, and the GPIO drive strengths associated with the GPIO bank of the Raspberry Pi.

The video timing configuration of the Raspberry Pi is documented on the Raspberry Pi website at (https://www.raspberrypi.org/documentation/hardware/raspberrypi/dpi/README.md). The syntax required to input a desired video timing is provided in Section 9.1. This includes both the video output timings (such as resolution and framerate) as well as the output format settings. The GPIO drive strength on the Raspberry Pi is configurable from 0 (2 mA) to 7 (16 mA) per pin. TI recommends using the minimum drive strength that still provides enough current capacity to meet the desired video timings. More information on the GPIO pads control is found at (https://www.raspberrypi.org/documentation/hardware/raspberrypi/gpio/gpio_pads_control.md).

Using the 2" ribbon cable provided with the DLPDLCR230NPEVM, a video output of 1920 × 1080 resolution from 58 to 61 Hz can be achieved. Video output configurations are limited by the maximum pixel clock (PCLK) which can be supported by the Raspberry Pi 4B over its GPIO interface. Table 9-1 lists the video timing configurations (minimum and maximum frame rate) evaluated by TI:

Table 9-1 Raspberry Pi Video Timing Settings for DLPDLCR230NPEVM (With Provided Ribbon Cable)
Configuration Field Minimum Framerate Timing Maximum Framerate Timing
Output Format Settings Output Format 5 (18-Bit RGB666, CFG 1) 5 (18-Bit RGB666, CFG 1)
RGB Order 1 (R-G-B) 1 (R-G-B)
Output Enable Mode 1 1
HSYNC Disable 0 0
VSYNC Disable 0 0
Output Enable Disable 0 0
HSYNC Polarity 0 0
VSYNC Polarity 0 0
Output Enable Polarity 0 0
HSYNC Phase 1 1
VSYNC Phase 1 1
Output Enable Phase 1 1
Hardware Settings GPIO Drive Strength 5 7
Horizontal Settings Active Pixels 1920 1920
Sync Polarity 0 0
Front Porch 20 20
Sync Pulse 10 10
Back Porch 10 10
Vertical Settings Active Lines 1080 1080
Sync Polarity 0 0
Front Porch 10 10
Sync Pulse 10 10
Back Porch 10 10
Sync Offset A 0 0
Sync Offset B 0 0
Other Settings Pixel Rep 0 0
Frame Rate 58 Hz 61 Hz
Interlaced 0 0
Pixel Frequency 125 MHz 132 MHz
Aspect Ratio Setting 3 3