Author Topic: RPI + HDMI2CSI: does it work? and what does work?  (Read 373 times)

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Offline DiTBho

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RPI + HDMI2CSI: does it work? and what does work?
« on: May 15, 2022, 01:51:04 pm »
The company "Geekworm" has an interesting toy for RPI: the C779!

It's a "camera serial interface(1)" version2, aka "CSI-2" Module with Toshiba TC358743XBG chip that accepts HDMI input up to 1080p@25fps and allows RPI(2) to capture and record videos though the v4l2-ctl  console tool.


Any experience?  :-//



(1) The Camera Serial Interface (CSI) is a specification of the Mobile Industry Processor Interface (MIPI) Alliance. It defines an interface between a camera and a host processor. The latest active interface specification is CSI-3 which was released in 2012.
 
Different Standards of MIPI CSI Interface:
  • MIPI CSI-1 was the original standard MIPI interface for cameras. It emerged as an architecture to define the interface between a camera and a host processor.
  • MIPI CSI-2 released in 2005. It uses either D-PHY or C-PHY (Both standards are set by the MIPI Alliance) as a physical layer option. The protocol is divided into the following layers:
    1. Physical Layer (C-PHY/D-PHY)
    2. Lane Merger Layer.
    3. Low Level Protocol Layer.
    4. Pixel to Byte Conversion Layer
    5. Application Layer

    Features:
    PHY variants supported: D-PHY 1.2, C-PHY 1.0 or "Combo PHY"
    Number of Virtual Channels: Four (4)
    Control Interface: I2C
    Line based transmission (Easy implementation, low gate count, matched data rates for sensor and link)
    Interrupt type: In-Band
    Supports { RGB, RAW, YUV, JPEG }
    Embedded Data
    CRC/ECC for payload & Header Protection
  • MIPI CSI-3 is a high-speed, bidirectional protocol primarily intended for image and video transmission between cameras and hosts within a multi-layered, peer-to-peer, UniPro-based M-PHY device network. Originally released in 2012, got re-released in version 1.1 in 2014.
(2) compatible with: Raspberry Pi { 4B, 3B+, 3B, 3A+, 2B, 2B+, Pi Zero , Zero W }


« Last Edit: May 15, 2022, 05:34:11 pm by DiTBho »
 

Offline DiTBho

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Re: RPI + HDMI2CSI: does it work? and what does work?
« Reply #1 on: May 15, 2022, 01:51:47 pm »
Has anyone already tried to connect VGA through a VGA-to-HDMI-adapter?
Code: [Select]
vga ----> VGA-to-HDMI (adapter) ----> HDMI-to-CSI-2 (C779) ----> RPI V4L
Does it work correctly?
« Last Edit: May 15, 2022, 05:31:56 pm by DiTBho »
 

Offline DiTBho

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Re: RPI + HDMI2CSI: does it work? and what does work?
« Reply #2 on: May 15, 2022, 04:34:42 pm »
Digging deeper, I found that C779 only supports video, doesn't support audio, but there are other modules(1) that take the incoming HDMI signal and converts it into a separate CSI signal and I2S audio signal.

I2S-Audio requires wiring to the expansion port of the RPI

(1) { C780, C790 }
« Last Edit: May 15, 2022, 05:34:41 pm by DiTBho »
 


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