usb to gpio can’t connect ucd9222

Is the UCD9222 powered? Also, check data and clock waveform and see if they have correct levels. The adapter has programmable internal pull-up resistors. You can adjust the internal pull-up resistor values by GUI.

Data should be high when there is no communication. Maybe you measured a wrong pin?

You can measure the data and clock lines when GUI is scanning the bus, and see if they have switching waveform.

The pin I measured should be right.  pin9 is clk and pin10 is data.

 then I scanning the bus and use the oscilloscope measure（remove my board, just measure from usb adapter）pin 9 (pmbus clk)(yellow) and pin 10 (pmbus data)(green)  in the picture.

and found that The level of pmbus data is 70mv  it seems that  abnormal .but the pmbus clk is 3.3v , seem normal.

 the usb adapter firmware version is 1.0.10, is it low?

what other problem should result the pumbus data can't be pulled high?   thanks

HI FERY:

  I use the  Fusion Design Online  on the desktop.

The data and clock  pull up can be choosed 2.2kΩ 1kΩ 668Ω and open drain on the  menu.

I choose 1k, then mesure and find the pin data 's level be 130mv ,and then choose 668 ,the result is 180mv.

for the clock the result is always 3.3v no matter what size I choose.

then I connect  the adapter with my board and The result is the same as the adapter no connect with my board .

I test my board (not connect with adapter pin). the pmbus clock pin and data pin are both 3.3v level.

The picture below is that  I connect  the adapter with my board .clk and adta both are be set 668 on the software menu.

why the data pin can't be Improved the level ?

is there something else I need to do?

thank you .

Hi  Fery Feng

NOW The new usb to gpio has been received. and I test the pin without connect any device besides the PC .find that  the DATA pin (pin 10) voltage is keep 0V regardless of pull-up resistor. I donot know why.

Are you using the same ribbon cable between both adapters?

Have you tried testing the pin directly from the adapter rather than on the ribbon cable?

Hi  Fery Feng:

 I sure the USB to GPIO is powered, and the green LED is on.

and when  I connect this USB to GPIO to the board, it do not function.

do I need update the firmware of the USB to gpio. now  the firmware version of the usb to gpio is 1.0.10 as the picture

 and what is  the  firmware version of  your  usb to gpio ?   thank you .

Firmware version 1.0.10 for USB-to-GPIO is fine.

Did you verify that the ribbon cable is OK?

You have indicated that the data and clock lines on the board are OK when the adapter is disconnected, which means you must have pullups on your board to a locally generated 3V3 source (the Alert line could be low if there was a condition present on the controller that would activate this pin with or without the adapter connected)

So it sounds as if there is some interaction between the board and the adapter.

Lets go over the connections on the ribbon cable from the adapter:

1) Pin 6 should be connected to GND on your board

2) Pin 7 is the Control Pin (used to enable/disable the controller), this is optional

3) Pin 8 is the Alert Line which is driven low by the controller when a fault/warn condition is present

4) Pin 9 is the CLK

5) Pin 10 is DAT

6) Pin 5 is 3V3 LDO reference voltage from the adapter, this should not be connected to a 3V3 source on your board,

Can you provide the schematic circuit for the connection between the ribbon cable and the UCD9222?