TUSB4041I: [On-Board Programming Tool] for EEPROM connected with TUSB4041

Max

Please accept my friendship request and I will send the tool to you.

Thanks
David

I accepted your request, please send me the tool

Hello David,

my hub is working with FTDI chips (FT231, FT2232D) and also with keyboard or mouse, but is not working with card reader or my debugger ICD3.
It seems to me like it is wokring at 12Mbit/s rates but not on 480Mbit/s rates. The windows device manager usually says that port reset failed.
Could it be because of impedance mismatch or difference in length of the D+ a D- lines? I tried to match both as much as possible...

Can you provide a schematic?

Regards,
JMMN

Here is PDF of my schematic.

Note: Hub is powered through 40pin connector from another board where there is 5V 2A power supply. Power consumption when connected to PC and with both FT2232Ds enumerated is around 50-60mA

Extension-USB-sch.pdf

Hi Maximilian,

Are ports 1 and 2 connected to the FT2232Ds or to external ports? It looks like both are populated in the schematic. Also, battery charging is enabled on all the downstream ports (pullups on PWRCTL lins) which may cause interoperability issues for devices that are permanently connected.

Which port do you typically connect the USB 2.0 device to? Can you confirm that VBUS to that port doesn't dip below 4.5V?

Regards,
JMMN

Hi JMMN,

connectors on all ports are populated, but resistors on D+ and D- lines of port 1 and 2 aren't (see DNI or DNP note). Also there are no pull-ups on PWRCTL, because those are marked DNI also.

I use connectors X4 and X5 for connecting an external devices. When I plug in the debugger, the voltage is 4.91V

I don't see anything in your schematic to explain the behavior. If FS/LS devices work then all the signals are connected correctly. Can you confirm that there is sufficient solder underneath the device? That is the main ground connection and it can cause problems if a solid connection is not made.

Hello JMMN,

I can't confirm if there is enough solder. The PCB assembly was done in a different company and I can't access the bottom pad, but there's more than 16 vias underneath the device to make a solid connection to the inner ground layer...

However, I criss-crossed the D+ and D- lines at the connector end (1 line goes from top to bottom layer and then back, while other goes only through the top layer) to match the pinout polarity. I didn't notice at the time I designed the board, that I can change the lines polarity in the EEPROM configuration...

Hi Maximilian,

Ideally, the differential pair signals would be matched length and routed on the same layer, but USB 2.0 is pretty forgiving and FS/LS traffic even more so. Can you provide any scope plots of the traffic between the TUSB4041 and the mouse during connect?

Regards,
JMMN

Hope this will be sufficient, I have a scope with only 200MHz bandwidth.

On attached images is the enumeration of USB keyboard HP KU-1156. The keyboard works, the USB flash drive does not...

Ok, that looks good. Can you try to get a scope plot of the USB 2.0 HS connection event? I understand the scope won't catch most of the signalling, I'm just trying to get an idea of how far it gets in the process. Also, after the USB 2.0 connection fails, do you see DP get pulled high by the downstream device?

Regards,
JMMN

Hi JMMN,

here are the plots of what happens when I try to connect a debugger...

Note: Green line is a D+ line

Well I can see that the USB 2.0 high speed handshake is attempted, but I can't determine why it fails. The most likely cause is signal quality or power. Please check that VBUS to the port doesn't dip during the handshake.

Here are the scopes with VBUS on channel 2 (blue one), but the voltage does not seem to clip...