
IX PERIPHERAL MODULES 7 (USB): USB FUNCTION CONTROLLER (USB)
IX-1-10
EPSON
S1C33E07 TECHNICAL MANUAL
Table IX.1.4.1.4 lists control items and statuses related to transaction processing on the EPa, EPb, EPc, and EPd
endpoints.
Table IX.1.4.1.4 Control Items and Statuses for Endpoints EPa, EPb, EPc, and EPd
Register/bit
EPx{x=a,b,c,d}Control.AutoForceNAK
EPx{x=a,b,c,d}Control.EnShortPkt
EPx{x=a,b,c,d}Control.
DisAF_NAK_Short
EPx{x=a,b,c,d}Control.ToggleStat
EPx{x=a,b,c,d}Control.ToggleSet
EPx{x=a,b,c,d}Control.ToggleClr
EPx{x=a,b,c,d}Control.ForceNAK
EPx{x=a,b,c,d}Control.ForceSTALL
EPx{x=a,b,c,d}IntStat.OUT_ShortACK,
EPx{x=a,b,c,d}IntStat.IN_TranACK,
EPx{x=a,b,c,d}IntStat.OUT_TranACK,
EPx{x=a,b,c,d}IntStat.IN_TranNAK,
EPx{x=a,b,c,d}IntStat.OUT_TranNAK,
EPx{x=a,b,c,d}IntStat.IN_TranErr,
EPx{x=a,b,c,d}IntStat.OUT_TranErr
Description
Sets the endpoint's EPx{x=a,b,c,d}Control.ForceNAK
bit whenever an OUT transaction is completed.
Enables transmission of short packets that are under
the maximum packet size for IN transactions. This
setting is cleared after the IN transaction that has
transmitted a short packet is completed.
In OUT transactions, reception of a short packet
automatically disables the function that sets the
endpoint's EPx{x=a,b,c,d}Control.ForceNAK bit.
Indicates the state of the toggle sequence bit.
Sets the toggle sequence bit.
Clears the toggle sequence bit.
Returns a NAK response to a transaction regardless of
the number of data or vacancies in the FIFO region.
Returns a STALL response to the transaction.
Indicates the result of the transaction.
Item
Set automatic
ForceNAK
Enable short packet
transmission
Disable automatic
ForceNAK setting
upon short packet
reception
Toggle sequence bit
Set toggle
Clear toggle
Forced NAK
response
STALL response
Transaction status
SETUP transaction
The SETUP transaction addressed to the EP0 endpoint of the macro's own node is automatically executed. (The
USB function must be enabled for this to happen.)
When a SETUP transaction is issued, all the contents of the data packet (8 bytes) are stored in the registers
EP0Setup_0 through EP0Setup_7, followed by an ACK response. Meanwhile, a RcvEP0SETUP status is issued
to the firmware.
If an error occurs during a SETUP transaction, no response or status is issued.
When the SETUP transaction is completed, the ForceNAK bit of the EP0ControlIN and EP0ControlOUT
registers are set and the ForceSTALL bit is cleared. The ToggleStat bit is also set. After the firmware completes
setting the EP0 endpoint and becomes ready to proceed to the next stage, clear the ForceNAK bit of the relevant
direction in the EP0ControlIN or EP0ControlOUT register.
Figure IX.1.4.1.1 illustrates how the SETUP transaction is executed.
(a) The host issues a SETUP token addressed to the EP0 endpoint of this node.
(b) Next, the host sends an 8-byte long data packet. The macro writes these data in the EP0Setup_0 through
EP0Setup_7 registers.
(c) The macro automatically returns an ACK response. In addition, it sets registers to be automatically set up
and issues a status to the firmware.
SETUP
a
ACK
c
DATA
b
Host to Device
Device to Host
Figure IX.1.4.1.1 SETUP Transaction