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I want to make a USB 2.0 Cable for some gadgets with a USB-C to USB-C connection. I want to intentionally make connector end = host, and the other connector end = device. I've read around that I can do this using resistors, without the need of attaching another wired connection to both ends, but I am not sure how.

Any guidance on how I can achieve this? The connectors I am using are the ones below.

Thanks!

connectors

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    \$\begingroup\$ A cable does not determine gender (host vs device), it's only a pass-through. What is your target application? It's unclear, please provide more details on what you are trying to achieve. \$\endgroup\$
    – eeintech
    Feb 25 '20 at 11:25
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    \$\begingroup\$ Note that 'host' and 'slave' are more then just names on a connector. You need the appropriate hardware behind it for it to function. \$\endgroup\$
    – Oldfart
    Feb 25 '20 at 11:48
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I want to intentionally make connector end = host, and the other connector end = device.

Generally the C-C cable is supposed to be symmetrical, and the host/device role is determined by Rp (host side) or Rd (device side) inside the corresponding receptacles, and the communication goes across one CC wire.

But your approach is also doable, although non-standard. The "device side" of your cable should have 5.1k pull-down on CC pin, and the "host end" should have a pull-up to VBUS.

However, you will need to decide what kind of capacity you should fake. 56k pull-up will provide information that your cable is 500 mA capable. This would be the safest option.

ADDENDUM: The above answer assumes that the cable does not connect CC pins on both ends along the cable. Otherwise, as LMS commented below, some systems might engage Power Delivery negotiations and increase VBUS above safe levels for CC receiver electronics.

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  • \$\begingroup\$ Just a slight note: the Rp pull-up isn't to Vbus because Vbus can increase to up to 20V, which could damage 'CC'-wire components. That's the easiest option for a resistor inside the cable, but it prevents standards compliance for USB-PD devices. Rp can pull up to any voltage under 5.5V as long as the result is the correct voltages on the CC wire (Tables 4-28 to 4-32 of the Type-C cable and connector spec). It might be worth looking into whether a resistor to Vconn (the other 'CC' wire) would be doable, as that gets 3.0-5.5 volts to power the electronic marker. \$\endgroup\$
    – LMS
    Mar 29 '20 at 20:25
  • \$\begingroup\$ @LMS, no, your concern about 20V is unfounded. Since the OP does not plan to connect CC wire along the cable, any PD communication will fail and VBUS will not be increased. But I can agree that Rp is usually to default +5VSAFE inside all host receptacles, and not to VBUS. \$\endgroup\$ Mar 29 '20 at 20:31
  • \$\begingroup\$ People reading this question in future might not be in exactly the same situation. \$\endgroup\$
    – LMS
    Mar 29 '20 at 20:33
  • \$\begingroup\$ @Ale..chenski Is there any way (in USB specs) to change/add resistors to reverse the host/device data roles (but keep the power roles set by the 56k/5.1k, so that the device then sources power to the host)? or maybe a spec causing the power sink to periodically try to be a data host in case of no connection? I have a more detailed question about this at electronics.stackexchange.com/questions/503384 \$\endgroup\$
    – bobuhito
    Jun 4 '20 at 5:10
  • \$\begingroup\$ @bobuhito, by default of CC pins pulls the power role of source is associated with host function, and sink is associated with data role as device. When a dual-role device flips it advertising from source to sink and back, the data role switches accordingly. There is no way to keep the data role and reverse it the sink/source role by means of resistors alone. The only way is to use Power Delivery communication. \$\endgroup\$ Jun 4 '20 at 5:29
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You need to use a pin which is called the ''CC pin'' see in the type-c pinout figure below:

enter image description here

since the USB type C connector allows the use of several pins, it enables the device to find out in what role to be in based on the CC Pin. it is pulled up and down via resistors on each termination, enabling the establishment of data roles between the ports.

For further info, check this link:

https://www.silabs.com/community/mcu/8-bit/knowledge-base.entry.html/2016/09/26/what_s_the_role_ofc-kQYe

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  • \$\begingroup\$ There is no connector called "CC pin", only... pins. Please provide more details to your answer, it is unclear what you are trying to suggest. \$\endgroup\$
    – eeintech
    Feb 25 '20 at 11:27
  • \$\begingroup\$ @Cisco25, please note that the Type-C plug defines only one CC pin, see the picture above. \$\endgroup\$ Mar 29 '20 at 20:09

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