![NXP Semiconductors LPC43Sxx Скачать руководство пользователя страница 851](http://html1.mh-extra.com/html/nxp-semiconductors/lpc43sxx/lpc43sxx_user-manual_1721827851.webp)
UM10503
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
851 of 1441
NXP Semiconductors
UM10503
Chapter 28: LPC43xx/LPC43Sxx Ethernet
28.6.33 DMA Operation mode register
The Operation Mode register establishes the Transmit and Receive operating modes and
commands. This register should be the last CSR to be written as part of DMA initialization.
24
EB2
Error bit 2
This bit indicates the type of error that caused a Bus Error (e.g., error response on the
AHB interface). This bits is valid only when bit 13 in this register is set. This field does
not generate an interrupt.
1 = Error during read transfer.
0 = Error during write transfer.
0
RO
25
EB3
Error bit 3
This bit indicates the type of error that caused a Bus Error (e.g., error response on the
AHB interface). This bits is valid only when bit 13 in this register is set. This field does
not generate an interrupt.
1 = Error during descriptor access.
0 = Error during data buffer access.
0
RO
31:26
-
Reserved
0
RO
Table 636. DMA Status register (DMA_STAT, address 0x4001 1014) bit description
…continued
Bit
Symbol
Description
Reset
value
Access
Table 637. DMA operation mode register (DMA_OP_MODE, address 0x4001 1018) bit description
Bit
Symbol
Description
Reset
value
Access
0
-
Reserved
0
RO
1
SR
Start/stop receive
When this bit is set, the Receive process is placed in the Running state. The DMA
attempts to acquire the descriptor from the Receive list and processes incoming
frames. Descriptor acquisition is attempted from the current position in the list, which
is the address set by the DMA_REC_DES_ADDR register or the position retained
when the Receive process was previously stopped. If no descriptor is owned by the
DMA, reception is suspended and Receive Buffer Unavailable bit (bit 7 in DMA_STAT
register) is set. The Start Receive command is effective only when reception has
stopped. If the command was issued before setting the DMA_REC_DES_ADDR,
DMA behavior is unpredictable.
0
R/W
2
OSF
Operate on second frame
When this bit is set, this bit instructs the DMA to process a second frame of Transmit
data even before status for first frame is obtained.
0
R/W
4:3
RTC
Receive threshold control
These two bits control the threshold level of the MTL Receive FIFO. Transfer
(request) to DMA starts when the frame size within the MTL Receive FIFO is larger
than the threshold. In addition, full frames with a length less than the threshold are
transferred automatically. These bits are valid only when the RSF bit is zero, and are
ignored when the RSF bit is set to 1.
00 = 64
01 = 32
10 = 96
11 = 128
0
R/W
5
-
Reserved
0
RO