USB Device Controller
1588
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Universal Serial Bus (USB)
29.3.1.21 Endpoint 0 Configuration Register (EP0)
This read/write register gives the device configuration for control endpoint 0.
Values depend on whether the reset action comes from USB device controller (CPU) or the USB host.
Figure 29-48. Endpoint 0 Configuration Register (EP0) [address = FCF78A40h]
15
14
13
12
11
10
8
Reserved
EP0_SIZE
Reserved
EP0_PTR
R-0
R/W-0
R-0
R/W-0
7
0
EP0_PTR
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value at reset
Table 29-52. Endpoint 0 Configuration Register (EP0) Field Descriptions
Bit
Field
Value
Description
15-14
Reserved
0
Reserved
13-12
EP0_SIZE
Endpoint 0 FIFO size. This field contains the endpoint 0 FIFO size value and must match the value
sent by the USB device controller to the USB host during the GET_DEVICE_DESCRIPTOR request
preceding configuration phase. Status flags (STAT_FLG.NON_ISO_FIFO_EMPTY and
STAT_FLG.NON_ISO_FIFO_FULL) and overrun and underrun conditions are based on this value
for all IN and OUT transactions to endpoint 0.The USB device controller must fill this field before
setting SYSCON1.CFG_LOCK.
0
8 bytes
1
16 bytes
2h
32 bytes
3h
64 bytes
Values after USB device controller hardware reset or USB reset are unchanged (which means that
value is unknown until first write access).
11
Reserved
0
Reserved
10-0
EP0_PTR
Endpoint 0 pointer. This field contains the address of the endpoint 0 pointer. Value 0 is not
permitted (reserved for setup FIFO).
Note: The pointer value must be set to a value < FFh, because the memory size is 2K bytes and a
pointer coded value = FFh corresponds to 2040 bytes. Addressing upper bytes results in memory
overlap.
0
Address = BASE (not permitted)
1h
Address = BASE + 8 bytes
2h
Address = BASE + 16 bytes
3h
Address = BASE + 24 bytes
:
:
FFh
Address = BASE + 2040 bytes
Values after USB device controller hardware reset or USB reset are unchanged (which means that
values are unknown until first write access).