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--- projects:usb-c-ify [2025/11/19 16:29] – admin
+++ projects:usb-c-ify [2025/11/19 22:51] (current) – [USB-C device roles] admin
@@ Line 3: / Line 3: @@
 ====== USB-C-ifying ======
-Having several different chargers for devices is tedious. Read about how to convert nearly everything into USB-C. \\
+Having several different cables and chargers for devices is tedious. Read about how to convert nearly everything into USB-C. \\
 It can be done two ways: \\
@@ Line 84: / Line 84: @@
 ==== TODO ====
+https://pcbartists.com/design/embedded/how-to-replace-microusb-with-usb-c-connector/ \\
+ In connectors that do not expose the CC1 and CC2 pins, they are simply connected internally to make things easy for you.
 USB-PD (65W) fast charger buck boards \\
 Bidirectional power bank modules: e.g. IP2369, read [[:projects:drill-powerbank-pd|DIY drill power bank]] \\
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 See USB-C pinout: [[https://pinoutguide.com/Slots/usb-type-c_pinout.shtml]] \\
 Read the [[https://hackaday.com/2016/04/22/hackaday-dictionary-usb-type-c/|hackaday.com USB-C dictionary]] \\
-Depending on device type there might be direct audio output on USB-C socket, which let's you use a passive adapter - unlike [[https://www.zmescience.com/science/news-science/x-rays-usb-c-cables/|Apple's lightning active audio adapter]] \\
+Depending on device type there might be direct audio output on USB-C socket, which let's you use a passive adapter - unlike [[https://www.ifixit.com/News/8448/apple-audio-adapter-teardown|Apple lightning active audio adapter]] and [[https://www.zmescience.com/science/news-science/x-rays-usb-c-cables/|Apple's USB-C cable]]. If you want to build your own active USB-C audio cable, read [[https://daumemo.com/diy-micro-usb-c-to-3-5mm-adapter-and-headphone-amplifier-part-4/]]. \\
 USB-C cables are not necessarily passive. There might be so called e-marker chips connected to the CC-pins. \\
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 | EPR E-marked Cable (Extended Power Range) | 5A | up to 240W (48V×5A) | E-marker reports EPR capability and 50V tolerance | E-marker chip with EPR fields | Needed for USB-PD 3.1 (28V/36V/48V) high-power charging |
 | Active USB-C Cable (USB4/High-Speed) | Typically 5A | up to 100W or 240W (if EPR) | E-marker reports current + data capability | E-marker + active signal conditioning | Used for USB4/Thunderbolt; power still determined by e-marker |
+====== USB-C device roles ======
+Read [[https://www.wandkey.com/usb-c-pinout-guide-and-features/]] for more info. \\
+USB-C devices have different roles: \\
+^ Device Role ^ Meaning ^ CC Resistors Used ^ CC Behavior ^ Notes ^
+| DFP (Downstream Facing Port) – Source | Provides power (charger, host) | Rp (56k, 22k, or 10k) | Pull-up on CC1 and/or CC2 | Advertises current: 56k=Default, 22k=1.5A, 10k=3A |
+| UFP (Upstream Facing Port) – Sink | Consumes power (phone, device) | Rd (5.1k) | Pull-down on CC1 and CC2 | Signals “I want power”; source detects Rd to begin supplying VBUS |
+| DRP (Dual Role Power) | Can be source *or* sink | Switches between Rp and Rd | Toggles Rp ↔ Rd periodically | Used in phones, laptops, some MCUs; role decided via toggling rules |
+| Accessory Mode (Audio/Debug) | Special accessories | Ra (~800Ω) | Pull-down on both CC pins | Triggers analog audio or debug accessory mode |
+| Cable Plug with E-Marker | Certified 5A or USB4 cable | No resistors; digital IC | Communicates via CC and powered over VCONN | Identifies cable capabilities (5A, EPR, USB4, length, vendor) |
+USB-C power roles are configured with CC-pin resistor values inside the devices - CC-pins MUST be connected. \\
+In connectors that do not expose the CC1 and CC2 pins, they are simply connected internally to make things easy for you. \\
+Selecting Sink or Source via the USB-C CC pins is conceptually equivalent to the micro-USB ID pin (4), which sets the OTG role by making the device act as the Source/Host (DFP) when the ID pin is grounded. \\
+^ Name ^ Value ^ Used By ^ Meaning ^
+| Rd (pull-down) | 5.1 kΩ | Sink (device that *consumes* power, e.g., phone) | “I am a sink. Please provide power.” |
+| Rp (pull-up) – Default | 56 kΩ | Source (charger/host) | “I can supply DEFAULT USB current (500 mA / 900 mA).” |
+| Rp (pull-up) – 1.5 A | 22 kΩ | Source (charger/host) | “I can supply 1.5 A.” |
+| Rp (pull-up) – 3.0 A | 10 kΩ | Source (charger/host) | “I can supply 3.0 A.” |
+| Ra (accessory pull-down) | ~800 Ω | Audio/Debug accessories | “I am an analog accessory (audio, debug, etc.).” |
+Everything else (voltages, 5A capability, data mode, PD negotiation) is digital, not resistor-coded. \\