LM3S9B81 Datasheet, PDF (965/1155 Pages) Texas Instruments – Stellaris® LM3S9B81 Microcontroller

Stellaris® LM3S9B81 Microcontroller
Bit/Field
7
Name
AUTOCL
Type
R/W
6
ISO
R/W
5
DMAEN
R/W
4
DISNYET / PIDERR R/W
3
DMAMOD
R/W
Reset
0
Description
Auto Clear
Value Description
0 No effect.
1 Enables the RXRDY bit to be automatically cleared when a packet
of USBRXMAXPn bytes has been unloaded from the receive
FIFO. When packets of less than the maximum packet size are
unloaded, RXRDY must be cleared manually. Care must be taken
when using µDMA to unload the receive FIFO as data is read
from the receive FIFO in 4 byte chunks regardless of the value
of the MAXLOAD field in the USBRXMAXPn register, see “DMA
Operation” on page 877.
0
Isochronous Transfers
Value Description
0 Enables the receive endpoint for isochronous transfers.
1 Enables the receive endpoint for bulk/interrupt transfers.
0
DMA Request Enable
Value Description
0 Disables the µDMA request for the receive endpoint.
1 Enables the µDMA request for the receive endpoint.
Note:
3 TX and 3 RX endpoints can be connected to the µDMA
module. If this bit is set for a particular endpoint, the DMAARX,
DMABRX, or DMACRX field in the USB DMA Select
(USBDMASEL) register must be programmed
correspondingly.
0
Disable NYET / PID Error
Value Description
0 No effect.
1 For bulk or interrupt transactions: Disables the sending of NYET
handshakes. When this bit is set, all successfully received
packets are acknowledged, including at the point at which the
FIFO becomes full.
For isochronous transactions: Indicates a PID error in the
received packet.
0
DMA Request Mode
Value Description
0 An interrupt is generated after every µDMA packet transfer.
1 An interrupt is generated only after the entire μDMA transfer is
complete.
Note: This bit must not be cleared either before or in the same cycle
as the above DMAEN bit is cleared.
June 29, 2010
965
Texas Instruments-Advance Information