PNX1500E NXP Semiconductors, PNX1500E Datasheet - Page 686

• Manufacturer Part Number: PNX1500E
• Manufacturer: NXP Semiconductors

Specifications of PNX1500E

• Lead Free Status / Rohs Status: Not Compliant

NXP Semiconductors
Volume 1 of 1
Table 2: LAN100 Registers
PNX15XX_PNX952X_SER_N_4
Product data sheet
Bit
This register is a byte address aligned to a word boundary (i.e., the two LSBs are fixed to 0). The register contains the
lowest address in the array of descriptors.
31:2
1:0
Offset 0x07 2134
This register is a byte address aligned to a double word boundary (i.e., the three LSBs are fixed to 0). The register contains
the lowest address in the array of status words.
31:3
2:0
Offset 0x07 2138
This register defines the number of descriptors in the descriptor array for which TxRtDescriptor is the base address. The
number of descriptors should match the number of statuse words. The register uses minus-one encoding, i.e., if the array
has 8 status elements, the value in the register should be 7.
31:16
15:0
Offset 0x07 213C
This register defines the descriptor that is going to be filled next by the software transmit driver. The transmit descriptor array
is empty as long as TxRtProduceIndex equals TxRtConsumeIndex. As soon as the array is not empty, the real-time transmit
hardware will start transmitting packets, if enabled. After a packet has been processed by software, software should
increment the TxRtProduceIndex, wrapping to 0 once TxRtDescriptorNumber has been reached. If the TxRtProduceIndex
equals TxRtConsumeIndex – 1, the descriptor array is full, and software should stop producing new descriptors until
hardware has transmitted some packets and updated the TxRtConsumeIndex.
31:16
15:0
Offset 0x07 2140
This register defines the descriptor that is going to be transmitted next by the hardware real-time transmit process. After a
packet has been transmitted, hardware increments the index, wrapping to 0 once TxRtDescriptorNumber has been
reached. If the TxRtConsumeIndex equals TxRtProduceIndex, the descriptor array is empty, and the transmit channel will
stop transmitting until software produces new descriptors.
31:16
15:0
Offset 0x07 2144
The BlockZone Register is only used in real-time/non-real-time arbitration mode, i.e., when the EnableQoS bit in the
Command register is deasserted. The BlockZone register defines a window before a real-time transmission time-stamp in
which no new non-real-time transmissions can be started, so as to free up the Ethernet for a pending real-time transmission.
The size of the BlockZone window in seconds is: BlockZone * T
No new non-real-time transfers will be started if: DescriptorTimeStamp < GlobalTimeStamp + BlockZone
The real-time transmission will start as soon as: DescriptorTimeStamp < GlobalTimeStamp.
31:16
Symbol
TxRtDescriptor
-
TxRtStatus
-
-
TxRtDescriptorNumber
-
TxRtProduceIndex
-
TxRtConsumeIndex
-
Real-time Transmit Status Base Address Register (TxRtStatus)
Real-time Transmit Number Of Descriptors Register (TxRtDescriptorNumber)
Real-time Transmit Produce Index Register (TxRtProduceIndex)
Real-time Transmit Consume Index Register (TxRtConsumeIndex)
Transmit Block Zone Register (BlockZone)
…Continued
Acces
s
R/W
R/W
-
R/W
-
R/W
-
RO
-
Value
0
0
0
0
Rev. 4.0 — 03 December 2007
Description
MSBs of real-time descriptor base address.
Fixed to 0.
MSBs of real-time transmit status base address.
Fixed to 0.
Unused
Number of descriptors in the descriptor array for which
TxRtDescriptor is the base address. The number of descriptors is
minus-one encoded.
Unused
Index of the descriptor that is going to be filled next by the real-time
transmit software driver.
Unused
Index of the descriptor that is going to be transmitted next by the
real-time Transmit Datapath.
Unused
Chapter 23: LAN100 — Ethernet Media Access Controller
Time-stamp Clock
PNX15xx/952x Series
© NXP B.V. 2007. All rights reserved.
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