Ethernet MAC
UG0331 User Guide Revision 15.0
400
Table 342 •
DMA_RX_CTRL
Bit Number
Name
Reset Value Description
[31:1]
Reserved
0x0
Reserved
0
Rx Enable
0x0
Setting this bit enables DMA receive packet transfers.
The bit is cleared by the built-in DMA controller whenever it
encounters an Rx overflow or bus error state.
Table 343 •
DMA_RX_DESC
Bit Number
Name
Reset Value Description
[31:1]
Top 30 bits of
Descriptor
Address
0x0
When RxEnable is set by the host, the built-in DMA controller reads
this register to discover the location in the host memory of the first
receive packet descriptor.
0
Ignored by the
DMA controller
0x0
All descriptors are 32-bit aligned in the host memory.
Table 344 •
DMA_RX_STATUS
Bit Number
Name
Reset Value Description
[31:24]
Reserved
0x0
Reserved
[23:16]
RxPktCount
0x0
The 8-bit receive packet counter that is incremented whenever the
built-in DMA controller successfully transfers a packet, and is
decremented whenever the host writes a ‘1’ to bit zero of this
register.
[16:4]
Reserved
0x0
Reserved
3
BusError
0x0
When set, this indicates that a host slave split, retry or error
response is received by the DMA controller.
2
RxOverflow
0x0
Set whenever the DMA controller reads a zero empty flag in the
descriptor it is processing.
1
Reserved
0x0
Reserved
0
RxPktReceived
0x0
When set, this indicates that one or more packets have been
successfully transferred. Writing a ‘1’ to this bit reduces the
RxPktCount value by one. The bit is cleared whenever RxPktCount
is zero.
Table 345 •
DMA_IRQ_MASK
Bit Number
Name
Reset Value Description
[31:8]
Reserved
0x0
Reserved
7
Bus Error Mask
0x0
Setting this bit to ‘1’ enables the Bus Error bit in the DMARxStatus
register as an interrupt source.
6
Rx Overflow
Mask
0x0
Setting this bit to ‘1’ enables the RxOverflow bit in the DMARxStatus
register as an interrupt source.
5
Reserved
0x0
Reserved