Register Descriptions
1335
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
M3 Universal Serial Bus (USB) Controller
Figure 18-35. USB Control and Status Endpoint 0 Low Register (USBCSRL0) in OTG B/Device
Mode
7
6
5
4
3
2
1
0
SETENDC
RXRDYC
STALL
SETEND
DATAEND
STALLED
TXRDY
RXRDY
W1C-0
W1C-0
R/W-0
R-0
R/W-0
R/W-0
R/W-0
R-0
LEGEND: R/W = Read/Write; -
n
= value after reset
Table 18-38. USB Control and Status Endpoint 0 Low Register
(USBCSRL0) in OTG B/Device Mode Field Descriptions
Bit
Field
Value
Description
7
SETENDC
Setup End Clear
0
No effect
1
Writing a 1 to this bit clears the SETEND bit.
6
RXRDYC
RXRDY Clear
0
No effect
1
Writing a 1 to this bit clears the RXRDY bit.
5
STALL
Send Stall.
0
No effect
1
Terminates the current transaction and transmits the STALL handshake.
This bit is cleared automatically after the STALL handshake is transmitted.
4
SETEND
Setup end.
0
A control transaction has not ended or ended after the DATAEND bit was set.
1
A control transaction has ended before the DATAEND bit has been set. The EP0 bit in the USBTXIS
register is also set in this situation.
This bit is cleared by writing a 1 to the SETENDC bit.
3
DATAEND
Data end.
0
No effect
1
Set this bit in the following situations:
• When setting TXRDY for the last data packet
• When clearing RXRDY after unloading the last data packet
• When setting TXRDY for a zero-length data packet
This bit is cleared automatically.
2
STALLED
Endpoint Stalled. Software must clear this bit.
0
A STALL handshake has not been transmitted.
1
A STALL handshake has been transmitted.
1
TXRDY
Transmit Packet Ready. If both the TXRDY and SETUP bits are set, a setup packet is sent. If just
TXRDY is set, an OUT packet is sent.
0
No transmit packet is ready.
1
Software sets this bit after loading an IN data packet into the TX FIFO. The EP0 bit in the USBTXIS
register is also set in this situation.
0
RXRDY
Receive Packet Ready.
0
No receive packet has been received.
1
A data packet has been received. The EP0 bit in the USBTXIS register is also set in this situation.
This bit is cleared by writing a 1 to the RXRDYC bit.