NXP Semiconductors LPC24XX UM10237 - Manual (Page 241)

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User manual Rev. 04 — 26 August 2009 241 of 792
NXP Semiconductors
UM10237
Chapter 11: LPC24XX Ethernet
The interrupt set register is write-only. Writing a 1 to a bit of the IntSet register sets the
corresponding bit in the status register. Writing a 0 will not affect the interrupt status.
7.4.5 Power-Down Register (PowerDown - 0xFFE0 0FF4)
The Power-Down register (PowerDown) is used to block all AHB accesses except
accesses to the PowerDown register. The register has an address of 0xFFE0 0FF4. The
bit definition of the register is listed in
Table 11–232 .
Setting the bit will return an error on all read and write accesses on the MACAHB interface
except for accesses to the PowerDown register.
8. Descriptor and status formats
This section defines the descriptor format for the transmit and receive scatter/gather DMA
engines. Each Ethernet frame can consist of one or more fragments. Each fragment
corresponds to a single descriptor. The DMA managers in the Ethernet block scatter (for
receive) and gather (for transmit) multiple fragments for a single Ethernet frame.
8.1 Receive descriptors and statuses
Figure 11–28 depicts the layout of the receive descriptors in memory.
Table 231. Interrupt Set register (IntSet - address 0xFFE0 0FEC) bit description
Bit Symbol Function Reset
value
0 RxOverrunIntSet Writing a ’1’ to one of these bits (0 to 7) sets the
corresponding status bit in interrupt status register
IntStatus. 0
1 RxErrorIntSet 0
2 RxFinishedIntSet 0
3 RxDoneIntSet 0
4 TxUnderrunIntSet 0
5 TxErrorIntSet 0
6 TxFinishedIntSet 0
7 TxDoneIntSet 0
11:8 - Unused 0x0
12 SoftIntSet Writing a ’1’ to one of these bits (12 and/or 13) sets the
corresponding status bit in interrupt status register
IntStatus. 0
13 WakeupIntSet 0
31:14 - Unused 0x0
Table 232. Power-Down register (PowerDown - address 0xFFE0 0FF4) bit description
Bit Symbol Function Reset
value
30:0 - Unused 0x0
31 PowerDownMACAHB If true, all AHB accesses will return a read/write error,
except accesses to the PowerDown register. 0