FOR
FOR
CY7C63411/12/13
CY7C63511/12/13
CY7C63612/13
16.0
Truth Tables
Table 16-1. USB Register Mode Encoding
Mode
Encoding
0000
Setup
ignore
accept
In
Out
Comments
Disable
Nak In/Out
ignore
NAK
ignore Ignore all USB traffic to this endpoint
NAK
Forced from Set-up on Control endpoint, from modes other
than 0000
0001
0010
0011
0100
Status Out Only
Stall In/Out
accept
accept
accept
ignore
stall
stall
check For Control endpoints
stall For Control endpoints
Ignore In/Out
Isochronous Out
ignore
ignore
ignore For Control endpoints
always Available to low speed devices, future USB spec
enhancements
0101
0110
Status In Only
Isochronous In
accept
ignore
TX 0
stall
For Control Endpoints
TX cnt
ignore Available to low speed devices, future USB spec
enhancements
0111
1000
1001
Nak Out
Ack Out
ignore
ignore
accept
ignore
ignore
TX 0
NAK
ACK
NAK
An ACK from mode 1001 --> 1000
This mode is changed by SIE on issuance of ACK --> 1000
An ACK from mode 1011 --> 1010
Nak Out - Status
In
1010
Ack Out - Status
In
accept
TX 0
ACK
This mode is changed by SIE on issuance of ACK --> 1010
1011
1100
1101
Nak In
Ack In
ignore
ignore
accept
NAK
TX cnt
NAK
ignore An ACK from mode 1101 --> 1100
ignore This mode is changed by SIE on issuance of ACK --> 1100
check An ACK from mode 1111 --> 111 Ack In - Status Out
Nak In - Status
Out
1110
1111
Ack In - Status
Out
accept
TX cnt
Check This mode is changed by SIE on issuance of ACK -->1110
The ‘In’ column represents the SIE’s response to the token type.
A disabled endpoint will remain such until firmware changes it, and all endpoints reset to disabled.
Any Setup packet to an enabled and accepting endpoint will be changed by the SIE to 0001 (NAKing). Any mode which indicates
the acceptance of a Setup will acknowledge it.
Most modes that control transactions involving an ending ACK will be changed by the SIE to a corresponding mode which NAKs
follow on packets.
A Control endpoint has three extra status bits for PID (Setup, In and Out), but must be placed in the correct mode to function as
such. Also a non-Control endpoint can be made to act as a Control endpoint if it is placed in a non appropriate mode.
A ‘check’ on an Out token during a Status transaction checks to see that the Out is of zero length and has a Data Toggle (DTOG)
of 1.
Document #: 38-08027 Rev. **
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