TUSB2077A: PORTDIS function of TUSB2077

K R RAHUL RAJ

Part Number: TUSB2077A
Other Parts Discussed in Thread: TPS2044B,

Tool/software:

hello team,

I have used TUSB2077A in my design and i have used TPS2044B power switches for OCP/Load enable. During overload, the TPS2044B raises OCP and the HUB pulls the EN down and the 5V to the load is cut off.

However, I did not understand the PORTDIS function entirely.

Could you please tell me if i could use PORTDIS by connecting it to a GPIO of my SOM to check if any of the ports get into OCP?

When will PORTDIS go HIGH and when does it go LOW ?

Thanks,

Rahul

9 months ago

0 Brian Zhou 9 months ago

TI__Guru**** 161766 points

HI Rahul:

When OCP happens, OVRCURx goes low and hub knows which port has overcurrent and force PWRONx low to disable power switch. PWRONx will keep low until overcurrent is cleared.

So you need to use PWRONx to enable power switch and connectting Fault pin of power switch to OVRCURx signal of hub.

PORTDIS is just output signal indicating if any ports got disabled or not..

Regards

Brian

0 K R RAHUL RAJ 9 months ago in reply to Brian Zhou

Prodigy 50 points

Thanks Brian,

Could you please tell me what "disabled" means? Will it be disabled during OCP ?

I want my MCU/SOM to understand that an OCP event has occurred with a USB PORT. I understand that i can use the same OVRCURx pin, but since there was PORTDIS, i thought to check if there's any way i could use that also ?

Thanks,

Rahul.

0 Brian Zhou 9 months ago in reply to K R RAHUL RAJ

TI__Guru**** 161766 points

Hi Rahul:

OVRCURx is used to detect overcurrent issue, PORTDIS is the result when detecting overcurrent on any port .

If hub OVRCURx pin is not connected to power switch Fault pin, hub will never know there is overcurrent issue happened, PORTDIS will always keep high.

Best

Brian

0 K R RAHUL RAJ 9 months ago in reply to Brian Zhou

Prodigy 50 points

okay, i will be connecting OVRCURx pin to HUB.

Just to double confirm, will PORTDIS go low if any of the OVRCURx pins go low ?

If not , could you please tell me some cases when PORTDIS will go LOW?

Thanks

0 Brian Zhou 9 months ago in reply to K R RAHUL RAJ

TI__Guru**** 161766 points

Hi Rahul:

PORTDIS will go low when any downstream port is disabled.

Best

Brian

0 K R RAHUL RAJ 8 months ago in reply to Brian Zhou

Prodigy 50 points

Brian Zhou

Can you elaborate the term "port is disabled" please ?

When does a PORT get disabled is my question , i'm sorry if i'm missing something.

When i tested the OCP of a particular port, the OCP pin went LOW and the EN went high which is correct, but i did not see PORTDIS go low. Why would that be ?

0 Brian Zhou 8 months ago in reply to K R RAHUL RAJ

TI__Guru**** 161766 points

Hi Rahul::

I tried on EVM, it seems PORTDIS signal only goes low in GANGed mode when overcurrent issue happened.

Best

Brian

0 K R RAHUL RAJ 8 months ago in reply to Brian Zhou

Prodigy 50 points

Thanks Brian,

I get it now, but is there any other function i can use so that my MCU/SOM knows that there is an OCP event other than using the OCP pins ?

Thanks

0 Brian Zhou 8 months ago in reply to K R RAHUL RAJ

TI__Guru**** 161766 points

Will, basically OCP signal is from Fault pin from power switch, you can connect Fault pin to MCU GPIO so that MCU will know if OCP event is happened and use another GPIO to control power switch on and off.

Best

Brian

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TUSB2077A: PORTDIS function of TUSB2077