6.10.2 DSS
The Display Subsystem (DSS) provides the logic to interface display peripherals. DSS includes a DMA engine as part of the integrated Display Controller (DISPC) module, which allows direct access to the frame buffer (system memory). Various pixel processing capabilities are supported, such as: color space conversion, filtering, scaling, etc.
The supported display interfaces (connections to external panel) are:
- One parallel interface, which can be used for MIPI® DPI 2.0, or BT-656 or BT-1120.
- One RFBI interface, supporting MIPI DBI 2.0.
The modules integrated in DSS are:
- Display Controller (DISPC), with the following main features
- One Direct Memory Access (DMA) engine
- One Video Pipeline (VID1) with color space conversion and in-loop up/down-scaling
- One Overlay Manager (OVR1)
- Active Matrix color support for 12/16/18/24-bit (truncated or dithered encoded pixel values)
- One Video Port (VP1) with programmable timing generator to support up to 148.5 MHz pixel clock video formats defined in CEA-861-E and VESA DMT standards
- Supported maximum FrameBuffer width of 4096 for all pixel formats
- Configurable output mode: progressive or interlaced
- Selection between RGB and YUV422 output pixel formats (YUV4:2:2 only available when BT-656 or BT-1120 output mode is enabled on the DPI interface)
- Stall Mode support for RFBI
- Remote Frame Buffer Interface (RFBI) module, with the following main features:
- Access to RFB direct "ARMSS interface":
- Sending commands and data to the RFB panel, received from DISPC or from ARMSS (through the 32-bit interconnect slave port)
- Reading data/status from the RFB through the 32-bit interconnect slave port
- RFB interface:
- 8/9/12/16-bit data bus (for up to QVGA @30fps)
- Two programmable configurations for two peripheral devices connected to the RFBI module
- Tearing Effect control logic: Horizontal Synchronization (HSync) and Vertical Synchronization (VSync) embedded in a single signal (TE) or using two signals (HS+VS)
- Programmable pixel memory and output formats
DSS provides two interfaces to SoC interconnect:
- One 128-bit master port (with MFLAG support). The DMA engine in DISPC uses this single master port to read data from SoC system memory.
- One 32-bit slave port. Used for configuration of the memory mapped registers inside DSS. It is further connected internally to DISPC and RFBI modules.
For more information, see section Display Subsystem (DSS) in chapter Peripherals of the Device TRM.