SPRADC8 june   2023 AM625-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Graphics Performance
  6. 3DSS Features
  7. 4Relevance of Functional Safety for Automotive Cluster Tell-tale Applications
  8. 5Safety Features on TI Sitara AM62x Processor
  9. 6Application-specific Task Partitioning and Safety Concept for Tell-tales
    1. 6.1 Common Cause Failures
  10. 7 TI’s Functional Safety Offerings
  11. 8Summary
  12. 9References

3 DSS Features

In addition to a GPU, the AM62x SoC also has a display subsystem (DSS). Figure 3-1 shows an overview of the DSS.

GUID-20230614-SS0I-7HZL-N304-LNVHBNS6PM4S-low.svg Figure 3-1 DSS Overview

The key features of the DSS are:

  1. Video Pipeline and Video Lite Pipeline:
    1. Two independent input pipelines
    2. Supports various RGB and YUV input formats
    3. Color space conversion from YUV to RGB
    4. Upscaling and downscaling (Video Lite Pipeline does not support scaling)
  2. Overlay Manager 1 and 2:
    1. Ability to perform composition of the two input pipelines
    2. Support for alpha blending
  3. Video Port 0 and 1:
    1. Supports gamma correction, color space rotation, and RGB or YUV output
  4. Dual display support and capability of driving 1920 × 1200 display at 60 FPS.
    1. Display 1: OLDITX can support native dual link LVDS panels, and Table 3-1 summarizes the various modes panels that can be connect with the DSS
    2. Display 2: Native RGB24 or DPI-based TDT panels
Table 3-1 OLDI Supported Modes
# of Modes LVDS Link Mode Link_1
(4 data + 1 clock)		 Link_2
(4 data + 1 clock)		 Description Supported
1 Single Link Mode - One Stream 165 MHz, wuxga (1920 × 1200 at 60 FPS) Unused One video stream Yes
2 Single Link Mode - One Stream Unused 165 MHz, wuxga (1920 × 1200 at 60 FPS) One video stream Yes
3 Single Link Mode - Two Stream (Duplicate) 165 MHz, wuxga (1920 × 1200 at 60 FPS) 165 MHz, wuxga (1920 × 1200 at 60 FPS) One stream duplicated in two links Yes
4 Dual Link Mode 85 MHz, wuxga (1920 × 1200 at 60 FPS) One video stream over two links Yes
Odd pixels Even pixels
5 Single Link Mode - Two Stream (Distinct) 165 MHz, wuxga (1920 × 1200 at 60 FPS) 165 MHz, wuxga (1920 × 1200 at 60 FPS) Two independent video streams No

For safety critical system applications, the DSS supports the safety features shown in Table 3-2 in the hardware.

Table 3-2 Safety Features in DSS Hardware
Feature Description
Data correctness check Verifies that the intended data is shown correctly on the display.
Freeze frame detection Provides a notification of a possible frame freeze when there is no change in the display frame over a multiple frame periods.

These features are implemented by collecting signatures from user-defined regions within each pipeline output frame and the final display output frame, and comparing them to reference signatures provided by the user (software) and or to previously saved signatures. The signature from each region is generated using a multiple input signature register (MISR) module. The 32-bit MISR module generates a unique signature for all pixel data within the Region of Interest (ROI) area.