Setup Transactions - Epson S2R72V18 Technical Manual

1. Functions
Table 1-9 shows the control items and status for general endpoint EPa, EPb, EPc, EPd, and EPe
transaction processing.
Item
Automatic ForceNAK
set
Short packet send
enable
Automatic ForceNAK
setting prohibition
using short packet
receipt
Toggle sequence bit
Toggle set
Toggle clear
Forced NAK
response
STALL response
Transaction status
1.3.2.1

SETUP Transactions

This LSI executes SETUP transactions addressed to endpoint EP0 on its own node regardless of
conditions. (The USB function must be enabled by the D_NegoControl.ActiveUSB bit.)
When a SETUP transaction is issued, the contents of all data packets (8 bytes) are placed in
registers D_EP0SETUP_0 to D_EP0SETUP_7 and an ACK response returned. RcvEP0SETUP
status is issued to the firmware, except for SetAddress() requests.
This LSI does not respond to or issue status information if an error occurs during a SETUP
transaction.
On completion of a SETUP transaction, the LSI sets the D_EP0ControlIN and D_EP0ControlOUT
register ForceNAK bits and clears the ForceSTALL bit. The ToggleStat bit and
D_SETUP_Control.ProtectEP0 bit are also set. When the firmware has completed the endpoint EP0
settings and is ready to proceed to the next stage, the SETUP_Control.ProtectEP0 bit should be
cleared and the corresponding direction ForceNAK bits cleared for the D_EP0ControlIN and
D_EP0ControlOUT registers.
10
Table 1-9 General endpoint control items and status
Register/bit
D_EPx{x=a-e}Control.AutoForceNAK
D_EPx{x=a-e}Control.EnShortPkt
D_EPx{x=a-e}Control.DisAF_NAK_Short
D_EPx{x=a-e}Control.ToggleStat
D_EPx{x=a-e}Control.ToggleSet
D_EPx{x=a-e}Control.ToggleClr
D_EPx{x=a-e}Control.ForceNAK
D_EPx{x=a-e}Control.ForceSTALL
D_EPx{x=a-e}IntStat.OUT_ShortACK,
D_EPx{x=a-e}IntStat.IN_TranACK,
D_EPx{x=a-e}IntStat.OUT_TranACK,
D_EPx{x=a-e}IntStat.IN_TranNAK,
D_EPx{x=a-e}IntStat.OUT_TranNAK,
D_EPx{x=a-e}IntStat.IN_TranErr,
D_EPx{x=a-e}I~tStat.OUT_TranErr
Sets the endpoint
D_EPx{x=a-e}Control.ForceNAK bit after each
out transaction is completed.
Enables the transmission of short packets
smaller than the max packet size for in
transactions. Cleared on completion of the in
transaction sending the short packet.
Prevents execution of the function (*) setting
the endpoint D_EPx{x=a-e}Control.ForceNAK
bit automatically on receiving a short packet in
the out transaction.
*: Active if not prevented by this bit.
Indicates the toggle sequence bit status.
Sets the toggle sequence bit.
Clears the toggle sequence bit.
Returns NAK to transactions regardless of FIFO
data size or free space size.
Returns STALL to transactions.
Indicates transaction results.
EPSON
S2R72V18 Technical Manual (Rev.1.00)
Description