Part Number: TUSB211
Other Parts Discussed in Thread: TUSB212
Hello,
I have a problem with interpretation of ENA_HS and CD signals.
My device utilizes a FT2232H USB HiSpeed chip and a single TUSB211 to compensate for cable loss.
The datasheet says that the CD signal of the TUSB211 should go high upon detection of USB connection. In my device it stays low when the device is connected and operating correctly. When I reset the chip by pulling RSTN low, then the CD signal goes low and returns high upon release of RSTN line. However, when I connect the device to a powerbank (no usb data transfer) then the CD stays always high... It seems that the CD signal is inverted? Am I correct ?
The ENA_HS signal is pulled high even when I connect the device to a powerbank! It also stays high when the usb device is operating correctly at HiSpeed.
When I reset the FT2232H chip, in order to make it re-initialize the USB connection, the CD stays low and ENA_HS stays high. The datasheet clearly says, that the ENA_HS will be "deasserted" when USB device disconnects.
I'have tried various EQ settings with 1.8k and 9.1k resistors. The CD and ENA_HS behavior is not influenced.
I do not have equipment to measure USB signal eye diagram, therefore i cannot determine if the TUSB211 is actually working or not :(
Schematic diagram of the TUSB211 part of the device:
And the PCB layout diagram. The PCB is 4-layer, red is top copper, yellow is ground plane directly underneath it.
I would appreciate any help / explanation of the chip behavior.
Maciej
