Timeline for Connecting CDC device to Android over USB-C, with concurrent charging. A cheap option?
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
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| Jun 16, 2022 at 7:25 | comment | added | topher217 | Say you implemented a USB-PD controller on your project and it negotiates to be the upstream facing port and provide power. Are you saying at this point the Android device can still remain in Host mode and negotiate a serial connection? Based on what I'm seeing in the docs, this is not possible. I think you still have to inform the Android device that you are a host implementing the Android Open Accessory protocol before the device will accept data transfer while charging. I'd love to be wrong about this, so if you have docs or evidence otherwise, I'd love to know how. | |
| Jun 16, 2022 at 6:40 | comment | added | topher217 | R u sure this is an argument between USB-C PD and the "old way"? I see nothing in the docs that suggests the Android Open Accessory protocol is specific to USB-C/PD. From the overview it looks like the power can only come from an external source when the phone is implementing Accessory Mode. Are you saying otherwise? If so, where can we find documentation on this specific to Android? i.e. I am aware of the upstream/downstream roles of PD, but not specific to Android and how to initiate a data connections and accept external pwr. | |
| Jul 22, 2020 at 5:58 | comment | added | Codo | Due the serial communication, the roles are fixed in your setup: The Android table is host, your PCB is the device. Without USB PD, power may only go from host to device, no matter how you wire the CC lines. | |
| Jul 21, 2020 at 18:21 | comment | added | Scott Porter | As said, I am using a pull-up on the CC line to initiate 500mA charging - I'm not basing this on pre USB-C tech, but my intention was to try to avoid using the whole PD controller and supporting circuit if possible due to the added BOM cost (practically doubling the cost of the device). I'm fully aware of the fact that the 8u2 cannot handle PD. Thanks. | |
| Jul 20, 2020 at 6:53 | history | answered | Codo | CC BY-SA 4.0 |