Register Map
13-50
13.2.22
Transmit Endpoint Configuration Registers (EP1_TX...EP15_TX)
The read/write transmit endpoint configuration registers (EP1_TX...
EP15_TX) configure the device for noncontrol transmit endpoint n (n: 115).
The endpoint size fields must match the values sent by the local host to the
USB host in response to the GET_CONFIGURATION_DESCRIPTOR during
configuration phase.
The local host must fill this field before setting the Cfg_Lock bit and must not
change the values once the Cfg_Lock bit is set.
Table 13–24. Transmit Endpoint Configuration Registers (EP1_TX...EP15_TX)
Bit
Name
Description
15
EPn_TX_Valid
Transmit endpoint n valid
14
EPn_TX_Size/Db
Transmit non-isochronous endpoint n double-buffer or transmit isochronous
endpoint n size[2]
13–12
EPn_TX_Size
Transmit endpoint n size
11
EPn_TX_Iso
Transmit isochronous endpoint n
10–0
EPn_TX_ptr
Transmit endpoint n pointer
13.2.22.1
EPn_TX[15].EPn_TX_Valid: Transmit Endpoint n Valid
This bit must be set by the local host to allow transmit endpoint n to be used
for USB transfers as part of the device configuration. If not set, all transactions
to this endpoint are ignored by the core.
1: Transmit endpoint n is part of the device configuration.
0: Transmit endpoint n does not exist for this configuration.
Value after local host reset is low, after USB reset is unchanged.
13.2.22.2
Transmit Endpoint n Double-Buffer(EPn_TX_Db)
This bit is only for non-isochronous endpoints used in DMA mode. For isochro-
nous endpoints, which are always double buffered, this bit is the endpoint size
MSB. For non-isochronous endpoints which are not used in a DMA transfer,
double-buffering is not provided.
This bit must be set by the local host to allow double buffering for transmit non-
isochronous endpoint n, when used in a DMA transfer. This is used to reduce
number of transactions resulting in NAK handshake.
1: Double buffer used for non-isochronous transmit endpoint n.
0: No double buffer for non-isochronous transmit endpoint n.
Value after local host or USB reset is unchanged.