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ADSP-BF537 Blackfin Processor Hardware Reference
8-33
Ethernet MAC
Ethernet Operation in the Sleep State
When the ADSP-BF536/ADSP-BF537 is in the sleep state, the Ethernet
MAC supports several levels of operation.
• The MAC may be powered down, by clearing
RE
and
TE
in the
operating modes register. In this lowest-power state, the MAC’s
internal clocks do not run, and the MAC neither transmits nor
responds to received frames. Note that the MAC will not receive a
PAUSE control frame in this state.
• The MAC receiver may be partially powered up in a
“wake-detect-only” state, but without enabling either the MAC
transmitter or MAC DMA. This state is selected by:
1. Setting
RE
and clearing
TE
in the operating modes register.
2. Setting either the
MPKE
(magic packet wake enable) or
RWKE
(remote wakeup frame enable) bits in the MAC wakeup
frame control and status register (
EMAC_WKUP_CTL
).
3. Clearing the capture wakeup frame (
CAPWKFRM
) bit in
EMAC_WKUP_CTL
.
When in the wake-detect-only state, the MAC receiver disables its
DMA interface, and does not request any DMA transfers (whether
data or status). Instead, the MAC receiver processes good incoming
frames through its remote wake-up and/or Magic Packet filters.
When a match is detected, the MAC signals a
WAKEDET
interrupt
(setting the
WAKEDET
status bit in the
EMAC_SYSSTAT
register). DMA
transfers do not resume until the
CAPWKFRM
bit is cleared.
• The MAC receiver may be fully powered up to both receive
and/or transmit frames, provided that only external memory (for
example, SDRAM) is used. Both the DMA data buffers and
descriptor structures must be in external memory, since internal L1
is unavailable when core clocks are stopped.
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
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Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...