cancel
Showing results for 
Search instead for 
Did you mean: 

USB Superspeed Peripherals

Anonymous
Not applicable

 Hi 

   

I have a problem wih the CYUSB3014-BZX.  it does not enumerate (windows does not detect a usb device) when the rising edge of the +5V supply is in bad shape.  I have to do a hard reset.  I try to hold the reset pin for 200ms while the +5V is unstable without succes (respecting the reset sequence in the datasheet).  We sometime have this problem on the CYUSB3014-BZX evaluation board.  What is the correct reset sequence?

   

 

   

Thanks.

0 Likes
8 Replies
Anonymous
Not applicable

Hi,

   

What do you mean when you say rising edge is of bad shape. Do you by any chance a oscilloscope screenshot of the same.

   

Surprised that even after using hardware reset after stable supply it is not working properly. Have you looked at the amount of noise on the line, would appreciate it if you can get a oscilloscope screenshot of the same.

   

Regards,

   

Anand

0 Likes
Anonymous
Not applicable
0 Likes
Anonymous
Not applicable

 This bad shape is made by the NCP361 a voltage supervier that check if the voltage is above 5.67v.  I tried to use a ds1816 on the reset to hold it for 200ms and I still had to push the reset buttom to get a good enumetation.  as if the cpu needs the reset to go up and down after a power to ensure good enumuration if there rise edge of the power is not smoot.  

   

 

   

Thanks

0 Likes
Bob_Marlowe
Expert II

Looks like a latch-up effect, not easy to come by.

   

Bob

0 Likes
Anonymous
Not applicable

 Hi,

   

So the yellow signal in the screenshot is the RESET# signal. Is my understanding right?

   

Regards,

   

Anand

0 Likes
Anonymous
Not applicable

One possible solution is to use a watchdog timer or software reset to reinitialize your device if does not get any USB connection. This fixed my problem wherein the device sometimes fails to enumerate properly after I reconnect the power supply.

0 Likes
Anonymous
Not applicable

Hi,

   

We will  make our FPGA reset the USB chip at power up.  

   

Here are two image, one that works and one that does not, it may also be the slow risetime off the bad shape +5V.

   

Thanks. 

0 Likes
Anonymous
Not applicable

 Here is a good signal that works when I bypass my NCP361.

0 Likes