Register Map
13-51
USB Function Module
13.2.22.3
Transmit Endpoint n Size (EPn_TX_Size)
EPn_TX.[14] bit description only applies for isochronous endpoints.
This field contains the endpoint n FIFO size value. Status flags (FIFO_Empty,
FIFO_Full) and underrun condition are based on this value for all IN transac-
tions to endpoint n (see Table 13–23, Endpoint n Size Values).
Value after local host reset or USB reset is unchanged.
13.2.22.4
Transmit Isochronous Endpoint n (EPn_TX_Iso)
This field must be set if the transmit endpoint n type is isochronous in the
desired device configuration. If not set, the endpoint type is bulk or interrupt
(the hardware does not distinguish bulk type from interrupt).
0: Transmit endpoint n type is isochronous.
1: Transmit endpoint n type is bulk or interrupt.
Value after local host or USB reset is unchanged.
13.2.22.5
Transmit Endpoint n Pointer (EPn_TX_ptr)
This field contains the address of the transmit endpoint n pointer.
For isochronous endpoints or for non-isochronous endpoints that allow
double-buffering, 2*TX buffer size must be reserved for ping-pong.
0x000: address = BASE
0x001: address = BASE + 8 bytes
0x002: address = BASE + 16 bytes
0x003: address = BASE + 24 bytes
...
0x0FF: address = BASE + 2040 bytes
Value after local host reset or USB reset is unchanged.
Set the pointer value higher than 0xFF, because the memory size is 2K bytes.
A pointer value equal to 0xFF corresponds to 2040 bytes: addressing upper
bytes results in memory overlap (see Section 13.4, Device Initialization).