Possibly something to do with the detection of VUSB and enumerating the device? I had what sounds like a similar issue on a HID Keyboard device where I would power cycle the host PC and the device would stop working until unplugged and plugged back in.
Turns out VUSB remains high when the PC was off (Most PCs keep their USB ports powered when shut down, can usually change this setting in the BIOS), and since VUSB detection was the only factor in controlling my code to connect/disconnect cleanly, the PSoC still thought it was connected and was getting hung up looking for responses from the host that would never come in.
Compound this on my checking for Endpoint ACK being while() loops instead of if() statements. It would hang on bGetEPAckState(1) infinitely and never re-enumerate with the host:
if (USB_IsConnected){
memcpy(&USB_Data_Out[USB_KEY_INDEX],USB_Keys,MAX_USB_KEYS);
while (!USBFS_bGetEPAckState(1));
USBFS_LoadInEP(1,USB_Data_Out,8);
}
USB_IsConnected would be true when VUSB was high and I'd get stuck in there.
I changed it over to this, using USBFS_CheckActivity() to determine my connection state, and removing the while loops:
if (USB_IsConnected){
if (USBFS_bGetEPAckState(1)){
USBFS_LoadInEP(1,USB_Data_Out,8);
}
/*No activity on bus, but no falling edge detected on VBUS, stop USB operation*/
if (!USBFS_CheckActivity()){
USB_IsConnected = false;
host_reset = true;
}
}
if (host_reset){
/*Check for reconnect*/
if (USBFS_bGetConfiguration()){
USBFS_EnableOutEP(2);
USBFS_LoadInEP(1,USB_Data_Out,8);
USB_IsConnected = true;
host_reset = false;
}
}
This let me detect when the device is powered, but the host is not responding. I then set a flag to start calling USBFS_bGetConfiguration() to determine when the host comes back and re-enumerate.
Hope this helps. Hard to tell what your issue is when you don't post any of your project.
