Datasheet

Section 14 Universal Serial Bus (USB)
Rev.7.00 Dec. 24, 2008 Page 518 of 698
REJ09B0074-0700
(1) Transition from normal operation to stall
(1-1)
Transaction request
USB
Reference
USB function module
(1-2)
Stall handshake
Stall
To (2-1) or (3-1)
To (1-3)
Normal status restored
(1-3)
(2) When Clear Feature is sent after EPnSTL has been cleared
(2-1)
Stall handshake
Transaction request
(2-2)
Clear Feature command
Clear Feature command
(2-3)
(3) When Clear Feature is sent before EPnSTL is cleared to 0
(3-1)
1. Set EPnSTL to 1 by
firmware
1. Receive IN/OUT
token from the host
2. Refer to EPnSTL
1. Transmit stall
handshake
1. Clear internal status
bit to 0
1. Clear i
nternal status
bit to 0
2. No change in
EPnSTL bit
1. SCME is set to 0
2. EPnSTL is set to 1
3. Set internal status
bit to 1
4. Transmit stall
handshake
1. Clear EPnSTL to 0
by firmware
2. Receive IN/OUT
token from the
host
3. Internal status bit
has been set to 1
4. EPnSTL is not
referred to
5. No change in
internal status bit
To (1-2)
Internal status bit
0
EPnSTL
0 → 1
Internal status bit
0
EPnSTL
1
Internal status bit
0 → 1
EPnSTL
1 (SCM
E = 0)
Internal status bit
1
EPnSTL
1 → 0
Internal status bit
1
EPnSTL
0
Internal status bit
1 → 0
EPnSTL
0
Internal status bit
1 → 0
EPnSTL
1
Figure 14.20 Forcible Stall by Firmware