LM3S3749 Datasheet, PDF (676/898 Pages) Texas Instruments – Stellaris® LM3S3749 Microcontroller

Universal Serial Bus (USB) Controller
Host
Device
Register 45: USB Maximum Transmit Data Endpoint 1 (USBTXMAXP1), offset
0x110
Register 46: USB Maximum Transmit Data Endpoint 2 (USBTXMAXP2), offset
0x120
Register 47: USB Maximum Transmit Data Endpoint 3 (USBTXMAXP3), offset
0x130
The USBTXMAXPn 16-bit register defines the maximum amount of data that can be transferred
through the transmit endpoint in a single operation.
Bits 10:0 define (in bytes) the maximum payload transmitted in a single transaction. The value set
can be up to 1024 bytes but is subject to the constraints placed by the USB Specification on packet
sizes for bulk, interrupt and isochronous transfers in full-speed operation.
The total amount of data represented by the value written to this register must not exceed the FIFO
size for the transmit endpoint, and must not exceed half the FIFO size if double-buffering is required.
If this register is changed after packets have been sent from the endpoint, the transmit endpoint
FIFO must be completely flushed (using the FLUSH bit in USBTXCSRLn) after writing the new value
to this register.
Note: USBTXMAXPn must be set to an even number of bytes for proper interrupt generation in
µDMA Basic Mode.
USB Maximum Transmit Data Endpoint 1 (USBTXMAXP1)
Base 0x4005.0000
Offset 0x110
Type R/W, reset 0x0000
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
MAXLOAD
Type RO
RO
RO
RO
RO
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit/Field
15:11
10:0
Name
reserved
MAXLOAD
Type
RO
R/W
Reset
0
0x000
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Maximum Payload
This field specifies the maximum payload in bytes per transaction.
676
November 17, 2011
Texas Instruments-Production Data