Hi Guenter, I'm bringing up a custom board based on NXPs I.MX8 processor that is powered on only by a USB type C. No battery is included. The PD interface chip is a PTN5110 from NXP. The problem I'm seeing is that when I power up the board through a Type C to Type C USB cable the board has the VBUS cut off in the early steps of the tcpm driver init. Now my question is, can the state machine modified and can we start from CONNECTED or TOGGLING state to jump over the first PORT_OFF state or there are any other implications and this is not possible? Please find bello the log from debugfs obtained if I supply externally VBUS to keep it alive while the bus is reset by the source. [ 2.660229] Setting voltage/current limit 0 mV 0 mA [ 2.660233] polarity 0 [ 2.661720] Requesting mux state 0, usb-role 0, orientation 0 [ 2.662788] state change INVALID_STATE -> SNK_UNATTACHED [ 2.663385] CC1: 0 -> 0, CC2: 0 -> 0 [state SNK_UNATTACHED, polarity 0, disconnected] [ 2.663394] 2-0050: registered [ 2.731746] Setting voltage/current limit 0 mV 0 mA [ 2.731751] polarity 0 [ 2.733689] Requesting mux state 0, usb-role 0, orientation 0 [ 2.734173] cc:=0 [ 2.734648] pending state change PORT_RESET -> PORT_RESET_WAIT_OFF @ 100 ms [ 2.735247] CC1: 0 -> 0, CC2: 0 -> 0 [state PORT_RESET, polarity 0, disconnected] [ 2.737602] CC1: 0 -> 0, CC2: 0 -> 0 [state PORT_RESET, polarity 0, disconnected] [ 2.837352] state change PORT_RESET -> PORT_RESET_WAIT_OFF [delayed 100 ms] [ 2.837358] pending state change PORT_RESET_WAIT_OFF -> SNK_UNATTACHED @ 920 ms [ 3.776941] state change PORT_RESET_WAIT_OFF -> SNK_UNATTACHED [delayed 920 ms] [ 3.776948] Start toggling [ 3.779848] CC1: 0 -> 0, CC2: 0 -> 5 [state TOGGLING, polarity 0, connected] [ 3.779854] state change TOGGLING -> SNK_ATTACH_WAIT [ 3.779862] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 200 ms [ 3.781714] CC1: 0 -> 0, CC2: 5 -> 5 [state SNK_ATTACH_WAIT, polarity 0, connected] [ 3.985026] CC1: 0 -> 0, CC2: 5 -> 5 [state SNK_ATTACH_WAIT, polarity 0, connected] [ 3.986785] state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED [delayed 200 ms] [ 3.986790] state change SNK_DEBOUNCED -> SNK_ATTACHED [ 3.986793] cc:=2 [ 3.987530] polarity 1 [ 3.990380] Requesting mux state 1, usb-role 2, orientation 2 [ 3.990869] state change SNK_ATTACHED -> SNK_STARTUP [ 3.990914] state change SNK_STARTUP -> SNK_DISCOVERY [ 3.990918] Setting voltage/current limit 5000 mV 3000 mA [ 3.990921] vbus=0 charge:=1 [ 3.991877] state change SNK_DISCOVERY -> SNK_WAIT_CAPABILITIES [ 3.992351] pending state change SNK_WAIT_CAPABILITIES -> SOFT_RESET_SEND @ 240 ms [ 3.992970] CC1: 0 -> 0, CC2: 5 -> 5 [state SNK_WAIT_CAPABILITIES, polarity 1, connected] [ 3.997181] PD RX, header: 0x1161 [1] [ 3.997188] PDO 0: type 0, 5000 mV, 3000 mA [SHU] [ 3.997191] state change SNK_WAIT_CAPABILITIES -> SNK_NEGOTIATE_CAPABILITIES [ 3.997200] cc=2 cc1=0 cc2=5 vbus=0 vconn=sink polarity=1 [ 3.997203] Requesting PDO 0: 5000 mV, 3000 mA [ 3.997206] PD TX, header: 0x1042 [ 4.004004] PD TX complete, status: 0 [ 4.004017] pending state change SNK_NEGOTIATE_CAPABILITIES -> HARD_RESET_SEND @ 60 ms [ 4.009962] PD RX, header: 0x363 [1] [ 4.009968] state change SNK_NEGOTIATE_CAPABILITIES -> SNK_TRANSITION_SINK [ 4.009980] pending state change SNK_TRANSITION_SINK -> HARD_RESET_SEND @ 500 ms [ 4.038937] PD RX, header: 0x566 [1] [ 4.038943] Setting voltage/current limit 5000 mV 3000 mA [ 4.038946] state change SNK_TRANSITION_SINK -> SNK_READY [ 4.057287] PD RX, header: 0x176f [1] [ 4.057293] Rx VDM cmd 0xff008001 type 0 cmd 1 len 1 [ 4.057305] PD TX, header: 0x124f [ 4.062033] PD TX complete, status: 0 Thank you and sorry for contacting you directly, Bogdan
