LM3S3748 Datasheet, PDF (547/753 Pages) List of Unclassifed Manufacturers – Microcontroller

LM3S3748 Microcontroller
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 MULT bit field contains the multiplication factor for the number of bytes in a given transaction.
For a single 64-byte bulk transfer, the multiplication factor is 1 so MULT should be written with 0. If
packet splitting is used, the multiplication factor allows for more than one transfer to be loaded into
the FIFO. A multiplication factor of 2 (MULT written to 1) allows two 64-byte packets to be written in
this endpoint's FIFO.
The total amount of data represented by the value written to this register (specified payload × m)
must not exceed the FIFO size for the transmit endpoint, and should 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 should be completely flushed (using the FLUSH bit in USBTXCSRL1n) after writing the new
value to this register.
Note: USBTXMAXPn must be set to an even number of bytes for proper interrupt generation in
DMA Mode 1.
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
MULT
MAXLOAD
Type R/W
R/W
R/W
R/W
R/W
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
MULT
MAXLOAD
Type
R/W
R/W
Reset
0x00
0x00
Description
Multiplier
Defines the maximum number of USB packets (that is, packets for
transmission over the USB) of the specified payload into which a single
data packet placed in the FIFO should be split, prior to transfer. The
value written to this register is one less than the desired multiplier. For
example, a value of 0 is a multiplier of 1.
Maximum Payload
The maximum payload in bytes per transaction.
April 08, 2008
547
Preliminary