Rainbow Electronics AT91CAP9S250A - Manual (Page 867)

867
6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
44.4.8.15 STALL
STALL is returned by a function in response to an IN token or after the data phase of an OUT or
in response to a PING transaction. STALL indicates that a function is unable to transmit or
receive data, or that a control pipe request is not supported.
• OUT
To stall an endpoint, set the FRCESTALL bit in UDPHS_EPTSETSTAx register and after the
STALL_SNT flag has been set, set the TOGGLE_SEG bit in the UDPHS_EPTCLRSTAx
register.
• IN
Set the FRCESTALL bit in UDPHS_EPTSETSTAx register.
Figure 44-15. Stall Handshake Data OUT Transfer
Figure 44-16. Stall Handshake Data IN Transfer
Token OUT Stall PID Data OUT
USB Bus
Packets
Cleared by Firmware
Set by Firmware
FRCESTALL
STALL_SNT
Set by Hardware
Interrupt Pending
Cleared by Firmware
Token IN Stall PID
USB Bus
Packets
Cleared by Firmware
Set by Firmware
FRCESTALL
STALL_SNT
Set by Hardware Cleared by Firmware
Interrupt Pending