TUSB2077A: Some quesitons

Hi,

TUSB2077 is a USB Full Speed hub only and cannot operate at USB High Speed. Does this failure occur when a device is connected? Do you have a schematic that can be reviewed?

Hi Sirs,

Thanks for your reply.

Please refer our schematic as below

NL is reserved.
The schematic is designed to be self-powered, individual-port power management

Hi,

What is the failure seen when testing? There are no obvious errors in the schematic. 

Hi Sirs,

Thanks for your reply.

The issue  is transmission speed too slow.
TUSB2077 only Full speed
However, the measured USB HUB transmission speed is only about 959kB/s.
Is there a way to adjust??

Hi,

There is no setting to adjust the transmitted data rate. How is this being measured? What is the customer expecting to see? How many devices are connected to the USB Hub during testing? How many board see this this "lowered" data rate?

Hi Sirs,

Thanks for your reply.

Our software test  use "one" USB flash drive
Transfer a large file with a fixed capacity

For example, 10MB is completed in ten seconds, and one second is 1MB.
Currently the boards are in the low speed state.

The others words,
Is the downstream transmission speed of the TUSB2077 dependent on the upstream??

What situation could be full speed?

Hi,

TUSB2077A cannot enumerate as a low speed devices due ti the pull up resistor on DP. (this resistor indicates FS devices per USB spec.) The lowered speed may be due several factors external to TUSB2077A such as SI conditions (long trace or cables) and SOC software. TUSB2077a also does not have any internal memory so TUSB2077A cannot be holding traffic back from the device. You can also check that TUSB2077A has enumerated at FS by using USBTree or USBView software and checking USB descriptors.