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Diffstat (limited to 'notes.md')
| -rw-r--r-- | notes.md | 72 |
1 files changed, 66 insertions, 6 deletions
@@ -85,14 +85,17 @@ Anyway, I need to support at least 640x480p@60Hz and 720x480@60Hz, and it would be nice to support 720x576p@50Hz. Note that PicoDVI supports these first two, but not the @50Hz one. -| format | bitrate | -|---------------|-----------------------| -| 640x480p@60Hz | 18,432,000 pixels/sec | -| 720x480p@60Hz | 20,736,000 pixels/sec | -| 720x576p@50Hz | 20,736,000 pixels/sec | +| format | bitrate | CEA-861 pixel freq | +|---------------|-----------------------|--------------------| +| 640x480p@60Hz | 18,432,000 pixels/sec | 25.200 MHz | +| 720x480p@60Hz | 20,736,000 pixels/sec | 27.027 MHz | +| 720x576p@50Hz | 20,736,000 pixels/sec | 27.000 MHz | https://forums.parallax.com/discussion/download/128730/Hdmi-1.4-1000008562-6364143185282736974850538.pdf -https://ia803002.us.archive.org/1/items/CEA-861-D/CEA-861-D.pdf +https://archive.org/details/CEA-861-D +https://glenwing.github.io/docs/DVI-1.0.pdf +https://www.cs.unc.edu/Research/stc/FAQs/Video/dvi_spec-V1_0.pdf +https://glenwing.github.io/docs/HDMI-1.0.pdf The RP2040 has several clocks: @@ -191,3 +194,60 @@ OpenBMC ---- https://hackaday.com/2022/08/26/bit-banged-ethernet-on-the-raspberry-pi-pico/ + +--- + +rough pricepoints +| HDMI socket | $0.85 | +| microHDMI socket | $1.36 | +| miniHDMI socket | $1.89 | +| DVI socket | $3.68 | + +--- + +- "USB" is a trademark of the USB Implementers Forum (USB-IF) +- "HDMI" is a trademark of HDMI Licensing Administrator, Inc. (HDMI LA) +- "DVI" was once a trademark of someone, but in the USA all relevant + trademarks have been canceled. + +--- + +The video-in socket is single-link DVI-D using an HDMI-style physical +receptacle. This makes it able to receive video from both +DVI-D-compliant sources and from HDMI-compliant sources; though it is +itself **not** HDMI-compliant. It supports the following resolutions: + - 640x480p @ 59.94/60Hz + - 720x480p @ 59.94/60Hz + - 720x576p @ 50Hz + +:explainer: + +> HDMI is perhaps easiest thought of as an extension to single-link +> DVI-D. There are 17 used pins on a single-link DVI-D connector; 17 +> of the 19 pins on an HDMI connector correspond 1:1 with these, and +> the additional 2 pins are optional "CEC" and "Utility" pins. HDMI +> starts talking as DVI-D, and enables additional non-DVI +> functionality based on the exchanged E-EDID device descriptors. +> That is: Compliant HDMI devices must work with DVI devices as long +> as they have an overlapping set of supported resolutions. +> +> Additionally, compliant HDMI sources are required to support at +> least one of the above resolutions, while compliant DVI sources are +> required to support 640x480p @ 60Hz. + +:rationale: + +> If it's DVI, why use an HDMI-style connector instead of a "more +> honest" DVI connector? +> +> Two reasons: +> +> - We anticipate that most DUTs that our users will want to plug +> into it have HDMI ports, and that our users are more likely to +> already have an HDMI cable than an HDMI←→DVI cable or HDMI←→DVI +> adapters. We also anticipate that users who actually do have +> DUTs with DVI ports already have DVI←→HDMI adapters. +> +> - HDMI-style sockets are much cheaper than DVI sockets; using a DVI +> socket would have increased the cost of the harness by several +> dollars. |