Hi Team,
Sorry to bother you.
We had used TPS2549 in a new project. We would like to know how to test IC D+/D- detection for BC1.2 (SDP, CDP and DCP), Samsung and Apple device. Do you have any test guide or tool can help us to do those test?
Thanks for your help and time.
Yours Faithfully
Redick Lee
Hello Redick,
Thanks for posting your question here on e2e. As far as testing for BC1.2 detection, a four channel oscilloscope is probably the best way to test this. You will want to connect to the following channels:
- VBUS
- I OUT (current output from VBUS)
- DP_IN
- DN_IN
What you are looking for in the signal levels on the D+/D- lines is that the portable device (device connected to the TPS2549) is advertising properly to the TPS2549 and that the TPS2549 is replying appropriately based on what mode you have it configured for. What you are looking for with the current output is that the current level that the portable device is drawing from the TPS2549 matches with BC1.2 mode that the two devices advertised and agreed upon.
I’ll give an example for if you are trying to test and verify for CDP mode. Here's a CDP timing diagram example found within the BC1.2 specification. The portable device starts the conversation by sending a signal on the shared D+ line. The source device detects this, and sends a response back on the D- line. The Portable device receives this response, and to verify that the D+ and D- lines are not shorted together (DCP mode), it sends another signal back through the D- line. The source device receives this signal through the D- line, but does not send back a response. Since the portable device never received a signal back on the D+ line, it knows that the D+ and D- lines are not shorted together, thus it is in CDP mode.
If this answered your question, please click This resolved my issue.
