USB TYPE C interface problem urgent help

olive888

USB TYPE C interface problem urgent help [Copy link]

 

I have used USB3300 to drive USB in other products before, and there was no problem. Recently, a project changed the USB interface to TYPE C, rewired, and soldered 3 boards. All of them had the same problem: the USB port connected to the computer was basically not recognized, but occasionally it could be recognized. In addition to the wiring problem, I would like to ask if there are any experts who have used TYPE C and see if there is any problem with the circuit in the figure below (DP pull-up resistor is just a backup)? Especially in terms of TYPE C interface:

dcexpert

The picture is not clear, but it looks like A5 and B5 are left floating. Here we need to set the resistor to identify the power supply.

olive888

dcexpert posted on 2018-11-16 21:27 The picture is not clear, but it looks like A5 and B5 are suspended. Here we need to set resistors to identify the power supply.

Doesn't TYPE C only connect VBUS GND DM DP?

olive888

dcexpert posted on 2018-11-16 21:27 The picture is not clear, but it looks like A5 and B5 are left hanging. Here we need to set the resistor to identify the power supply.

Aren't there only 4 wires in the TYPE C line?

dcexpert

olive888 posted on 2018-11-16 21:42 Aren't there only 4 wires in the TYPE C cable?

The standard type C has 24 wires, half on the positive and half on the negative. The simplified version has 16 wires. Type C is divided into two parts: communication and power control. I guess you don't use the power part, so you can ignore it. The main thing is communication. DP and DM are the same as before, but it has a voltage recognition function. Only when it is recognized can it normally supply power to the outside through USB. You need to find some information about this part. If there is no special requirement, usually a 5.1K resistor is connected to the ground on A5 and B5.

dcexpert

olive888 posted on 2018-11-16 21:42 Doesn't TYPE C only connect VBUS GND DM DP?

Type C is much more complicated than USB 2.0, especially the power supply part.

dcexpert

This is part of the circuit I used, for your reference.

olive888

dcexpert posted on 2018-11-16 21:58 This is part of the circuit I used, for your reference.

This is the TYPE C interface definition I used, what do you think should be changed?

dcexpert

olive888 posted on 2018-11-16 22:16 This is the TYPE C interface definition I use. What do you think should be changed?

Refer to the picture above

olive888

DP1 and DP2, DN1 and DN2 are connected together respectively?

mounthill

It is recommended to check the PCB layout to see if it is differential routing and whether the impedance is matched.

olive888

dcexpert posted on 2018-11-16 23:37 Refer to the above figure

As shown in the figure below, if two groups of DM and DN are to be connected, without adding vias, they have to go through a pin next to them (pin 9, the fourth pin from the left, defined as SUB1), and the differential traces are also asymmetrical and of unequal length. I wonder if this kind of trace will work?

dcexpert

The other pins are all useful and cannot be used at will, which will cause many problems. If the requirements are not high, it does not matter if there is no differential line, especially when it is only used as USB2.0.

olive888

dcexpert posted on 2018-11-20 09:42 Other pins are useful and cannot be borrowed at will, which will cause many problems. When the requirements are not high, it doesn’t matter if there is no differential line, especially when it is only...

Thank you! Now I have removed the pads and only borrowed them

olive888

dcexpert posted on 2018-11-20 09:42 Other pins are useful and cannot be used at will, which will cause many problems. When the requirements are not high, it doesn’t matter if there is no differential line, especially when it is only...

Redraw the PCB, and now it can be connected to the computer. I found that CC1 and CC2 can be connected without the 5.1K resistor, and they can be connected even when the test software is opened. I don’t know what the difference is between connecting and not connecting?

dcexpert

olive888 posted on 2019-1-10 15:38 I re-drew the PCB and now it can be connected to the computer. I found that CC1 and CC2 can be connected without the 5.1K resistor, and they can be connected when the test software is opened...

It is required in the standard to identify the device and output a certain power. Some chips may not be so strict and can output without it, or the power obtained is relatively small.

yanbao

The moderator explained it well