In the SL11H (slave mode) and SL11, does the "Send Stall" bit (bit 5) of the Endpoint Control Register(s) need to be reset for every transaction?  Or is it a sticky bit?

Question: In the SL11H (slave mode) and SL11, does the "Send Stall" bit (bit 5) of the Endpoint Control Register(s) need to be reset for every transaction?  Or is it a sticky bit?

 

Answer:

The Send Stall bit (bit 5) of the Endpoint Control Registers is a sticky bit and needs to cleared by firmware.  Otherwise once set, each transaction will be STALLed.



Everytime a packet is STALLed an USB Done interrupt will be generated giving the opportunity to monitor and clear the Send Stall bit.