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Help me !!!, USBUART_DataIsReady() not ready | Cypress Semiconductor

Help me !!!, USBUART_DataIsReady() not ready

Summary: 1 Reply, Latest post by SRAM on 30 Oct 2014 02:42 AM PDT
Verified Answers: 0
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jjcomB's picture
1 post

i'm using CY8CKIT-050 Psoc-5LP Development kit

i use USBUART CDC connect to pc.
if i connect usb after window boot finnish. it work well
if i connect usb cable before turn on Pc
and then i boot pc it doesn`t work.
USBUART_DataIsReady() != 0 is false.
if i remove and plug cable (or reset) it work again.
but i don't want to do this way.
what should i do.
thank you.
ps. sorry for My Bad English

SRAM's picture
Cypress Employee
50 posts


When you connect the device to PC before you start it and then you start the PC , the BIOS will try to enumerate the device . In that case  the while(!USBUART_1_GetConfiguration()); will pass and device will enter into the While(1)  and do the application.

When the PC exits the BIOS and enters into the Normal mode , the PC will not know that this device has been connected and it will try to enumerate this device again . However in our code we handle the enumeration only outside the While(1) loop . We dont handle the enumeration inside it . 

You need to modify the application code to handle the enumeration inside . You can use the USBFS_CheckActivity() API to see if you are have any USB Activity . If the activity does not happen for more than 1 second , then do the enumeration code (while(!USBUART_1_GetConfiguration());) again and see if it works .

If you are still facing an issue please create a Technical support case . Our engineers will assist you.


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