plankton_cc_flip_check

Source code: plankton_cc_flip_check.py

USB type-C CC line polarity check and operation flip test w/ Plankton-Raiden.

Description

This test flips the polarity bit of the USB type-C. Usually, the test will come along with other USB type-C test, for example, CC1/CC2 USB performance (removable_storage.py).

Automated test is unstable, you may have to retry. The Plankton-Raiden board guesses the polarity bit everytime SetDeviceEngaged(). Then it tries to flip the CC polarity to the another side. We have found that we need to charge the DUT in order to flip, and because of the charge action, the Plankton-Raiden board guesses the logical polarity bit again (you can find that the polarity is switching between CC1 and CC2 back-and-forth) and thus the flipping is unstable.

Test Procedure

This test can be tested manualy with the help from operator or automatically.

For normal USB type-C cable, this is a manual test with the help from operator:

1. Check USB type-C cable connected direction is right by CC polarity

2. Show operation instruction for cable flipping to test another CC line.

For double CC cable, this is an automated test:

• This test can flip CC automatically or you can set Arg double_cc_flip_target as ‘CC1’ or ‘CC2’ to indicate the final CC position.

• If test scheme can guarantee double CC cable connection is not twisted, that is, Plankton CC1 is connected to DUT CC1, then it can set Arg double_cc_quick_check as True to accelerate the test.

Dependency

• For manual test, you need a normal USB type-C cable to connect with Plankton-Raiden board.

• For automated test, you need a double CC cable to connection with Plankton-Raiden board.

Examples

To manual test with a dummy BFTFixture by asking operator to flip the cable, add this in test list:

{
  "pytest_name": "plankton_cc_flip_check",
  "args": {
    "bft_fixture": {
      "class_name":
        "cros.factory.test.fixture.dummy_bft_fixture.DummyBFTFixture",
      "params": {}
    },
    "ask_flip_operation": true,
    "usb_c_index": 0,
    "state_src_ready": "SNK_READY"
  }
}

Automated test with a dolphin BFTFixture and flipping the polarity to CC1:

{
  "pytest_name": "plankton_cc_flip_check",
  "args": {
    "bft_fixture": {
      "class_name":
        "cros.factory.test.fixture.dummy_bft_fixture.DummyBFTFixture",
      "params": {}
    },
    "double_cc_flip_target": "CC1",
    "usb_c_index": 1,
    "state_src_ready": "SNK_READY"
  }
}

Test Arguments

Name	Type	Description
bft_fixture	dict	A dictionary with the following items: class_name Fully-qualified class name of the BFTFixture implementation to use. params A dictionary of parameters for the BFTFixture class’s Init() method. The default value of None means that no BFT fixture is used.
adb_remote_test	bool	(optional; default: False) Run test against remote ADB target.
usb_c_index	int	Index of DUT USB_C port
original_enabled_cc	str, None	(optional; default: None) Set “CC1” or “CC2” if you want to check what CC pin is enabled now. There is no check if it is not set.
ask_flip_operation	bool	(optional; default: False) Determine whether to ask operator to flip cable.
double_cc_flip_target	str, None	(optional; default: None) If using double CC cable, set either “CC1” or “CC2” for the target to flip. Flip anyway if this is not set.
double_cc_quick_check	bool	(optional; default: False) If using double CC cable, set True if you guarantee CC pair is not reversed. CC polarity in Plankton side implies DUT side.
timeout_secs	int	(optional; default: 0) Timeout seconds for operation, set 0 for operator pressing enter key to finish operation.
state_src_ready	int, str	(optional; default: 22) State number of pd state SRC_READY.
wait_dut_reconnect_secs	int	(optional; default: 5) Wait DUT to reconnect for n seconds after CC flip. This is required if remote DUT might be disconnected a while after CC flip, e.g. DUT has no battery and will reboot on CC flip. If n equals to 0, will wait forever.
init_cc_state_retry_times	int	(optional; default: 3) Retry times for init CC state.