TPS65986: BC1.2 detection problems (DCP showing as SDP)

Hi Eric,

I'm sorry you're having problems. Firstly, I would like to do some modification on Apple chargers. 

Apple chargers don't follow BC1.2 specs. BC1.2 can only support up to 7.5W(5V/1.5A). I have done the test on Apple 12W adapter without any load, the voltage on D+ and D- is 2.7V which means clearly that Apple 12W adapter is not BC1.2 DCP or SDP. 

Unfortunately, we don't have the Cable Matters charger at hand, it can support up to 75W, please make sure if it can be used as a standard BC1.2 charger.

The register 0x3F can check the power status of BC1.2 shown in picture below:

For more information, the link below might help better understand the Apple charger.

On an Apple 12W USB Charger, how are the D+ and D- lines configured?

I hope it helps and solves your problem, PLEASE select  This resolved my issue  

Best Regards,

Hao

This answer about allowed DCP power levels is NOT true, to my understanding.  Per BC1.2 spec, one of the updates from BC1.1 to BC1.2, was specifically to allow DCP to output more than 1.5A.   Figure 4-2, in section 4.4.1 seems to specifically show a Green Line that goes up to ~4.75A, and comment "All Curves Allowed".  I tried to paste below, hopefully it comes through. 

However, I understand for DCP, D+/D- should be shorted, and as you found, the Apple Charger had 2.7V, which is clearly not shorted.   Any recommendation on how to deal with these, and get more of the available power from the charger?   (SDP reporting will cause current clamp at 500mA, to be spec compliant, right?)

Update to this question....   we better understand and agree that the original 2 chargers are not BC1.2 compliant, and TPS65986 does not have non-compliant charger detection feature.   However, we've done some testing with a new charger we believe is BC1.2 compliant, and are getting varying detection report sometimes as DCP, sometimes as SDP.  Would like to understand if you have any ideas, or have done any testing with this charger:

Motorola:  https://www.motorola.com/us/products/turbo-power-15-wall-charger

Characteristics

• VBUS [no load] ~5.1V
• D+/D-  ~15R (zero(0) voltage drop across this pins)

Observation(s):

1. Detection is still inconsistent. Failure rate as high as 20% where detected as SDP.
2. It seems that there are periods when the detection is consistent even after 20 retries. But when it detection start's failing i.e. SDP detected, failure rate is as high as 20%.

We also checked register dumps after successful detect (DCP) and unsuccessful (SDP) and only differences are in 0x3F and 0x6E registers (note:  0x6E is tagged as "reserved" in TRM)

After DCP successful detect:

0x3F:  3:  02 73 00

0x6E:  9:  08 40 20 b8 07 01 00 00 00

After SDP unsuccessful detect

0x3F:  3:  02 13 00

0x6E:  9:  08 40 20 18 47 01 00 00 00

Hao,

Have you been able to test/replicate?   Also, do you have a list of BC1.2 compliant chargers that we have tested with, that we can provide?   Thanks.