Chapter 11. Ethernet Module
11-15
Programming Model
11.5.5 Receive Descriptor Active Register (R_DES_ACTIVE)
The R_DES_ACTIVE register, Figure 11-8, is a command register that should be written
by the user to indicate that the receive descriptor ring has been updated (empty receive
buffers have been produced by the driver with the E bit set).
The R_DES_ACTIVE bit is set whenever the register is written. This is independent of the
data actually written by the user. When set, the FEC polls the receive descriptor ring and
processes receive frames (provided ETHER_EN is also set). As soon as the FEC polls a
receive descriptor whose E bit is not set, it clears the R_DES_ACTIVE bit and stops polling
the receive descriptor ring.
The R_DES_ACTIVE register is cleared at reset and when ETHER_EN is cleared.
31
16
Field
—
Reset
0000_0000_0000_0000
R/W
Read Only
15
4
3
2
1
0
Field
—
IVEC
—
Reset
0000_0000_0000_0000
R/W
Read Only
Addr
MBAR + 0x84C
Figure 11-7. Interrupt Vector Status Register (IVEC)
Table 11-10. IVEC Field Descriptions
Bit
Name
Description
31–4
—
Reserved, should be cleared.
3–2
IVEC
Interrupt vector. IVEC gives the highest outstanding priority FEC interrupt. The bit field
meanings (from low priority to high priority) are as follows:
00 No pending FEC interrupt
01 Non-time critical interrupt (All interrupts except TXB, TXF, RXB, and RXF.)
10 Transmit interrupt
11 Receive interrupt
1–0
—
Reserved, should be cleared.
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
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Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
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Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
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Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...