HS_Media independent interface (MII)
RM0082
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Doc ID 018672 Rev 1
24.3.6
Power management module (PMT)
This section describes the power management (PMT) mechanism as supported by the
MAC. PMT supports the reception of network (remote) wake-up frames and Magic Packet
frames. PMT does not perform the clock gate function, but generates interrupts for wake-up
frames and Magic Packets received by the MAC. The PMT block sits on the receiver path of
the MAC and is enabled with remote wake-up frame enable and Magic Packet enable.
These enables are in the
PMT Control and Status Register (Register11, MAC)
and are
programmed by the Application.
24.4 DMA
descriptors
The DMA Controller operates two descriptor lists, one for transmission and one for
reception. The base address of each list is written into DMA Register3 (Receive Descriptor
List Address,
) and Register4 (Transmit Descriptor List Address,
), respectively.
Each descriptor list (both for transmission and for reception) consists of a set of descriptor,
and each descriptor is provided with the following fields:
●
The status of the received/transmitted frames together with descriptor ownership
information,
●
A set of control bits,
●
The byte-count of the two pointed data buffers,
●
The address pointers of the two data buffers.
Depending on the contents of the 2nd data buffer of the last descriptor in the list, two
different lists can result (as depicted in
)
●
A ring structure
: the list is implicitly forward linked, each descriptor points to two data
buffers, and the last descriptor points back to the first entry of the list;
●
A chain structure
: the list is explicitly forward linked by using the 2nd address pointer
of each descriptor to point the next descriptor in the list.
