pnx1500 NXP Semiconductors, pnx1500 Datasheet - Page 685

• Manufacturer Part Number: pnx1500
• Description: Pnx15xx Series Connected Media Processor
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Volume 1 of 1
Table 2: LAN100 Registers
PNX15XX_SER_3
Product data sheet
Bit
This register indexes the descriptor that is to be processed next by the software receive driver. The receive array is empty as
long as RxProduceIndex equals RxConsumeIndex. As soon as the array is not empty, software can process the packet
pointed to by RxConsumeIndex. After a packet has been processed by software, software should increment the
RxConsumeIndex register, wrapping to 0 once the RxDescriptorNumber has been reached. If the RxProduceIndex equals
RxConsumeIndex – 1, the array is full, and any further packets being received will cause a buffer overrun error.
31:16
15:0
Offset 0x07 211C
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 2120
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 statuses.
31:3
2:0
Offset 0x07 2124
This register defines the number of descriptors in the descriptor array for which TxDescriptor is the base address. The
number of descriptors should match the number of statuses. 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 2128
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 TxProduceIndex equals TxConsumeIndex. As soon as the array is not empty, the non-real-time transmit
hardware will start transmitting packets, if enabled. After a packet has been processed by software, software should
increment the TxProduceIndex, wrapping to 0 once the TxDescriptorNumber has been reached. If the TxProduceIndex
equals TxConsumeIndex – 1, the descriptor array is full and software should stop producing new descriptors until hardware
has transmitted some packets and updated the TxConsumeIndex.
31:16
15:0
Offset 0x07 212C
This register defines the descriptor that is going to be transmitted next by the hardware non-real-time transmit process. After
a packet has been transmitted, hardware increments the index, wrapping to 0 once TxDescriptorNumber has been reached.
If the TxConsumeIndex equals TxProduceIndex, the descriptor array is empty, and the transmit channel will stop
transmitting until software produces new descriptors.
31:16
15:0
Offset 0x07 2130
Symbol
-
RxConsumeIndex
TxDescriptor
-
TxStatus
-
-
TxDescriptorNumber
-
TxProduceIndex
-
TxConsumeIndex
Non-real-time Transmit Descriptor Base Address Register (TxDescriptor)
Non-real-time Transmit Status Base Address Register (TxStatus)
Non-real-time Transmit Number Of Descriptors Register (TxDescriptorNumber)
Non-real-time Transmit Produce Index (TxProduceIndex)
Non-real-time Transmit Consume Index (TxConsumeIndex)
Real-time Transmit Descriptor Base Address Register (TxRtDescriptor)
…Continued
Acces
s
-
R/W
R/W
RO
R/W
RO
-
R/W
-
R/W
-
RO
Value
0
0
0
0
0
0
0
Rev. 3 — 17 March 2006
Description
Unused
Index of the descriptor that is going to be processed next by the
receive software.
MSBs of non-real-time descriptor base address
Fixed to 2’b00
MSBs of non-real-time transmit status base address
Fixed to 0
Unused
Number of descriptors in the descriptor array for which TxDescriptor
is the base address. The register is minus-one encoded
Unused
Index of the descriptor that is going to be filled next by the
non-real-time transmit software driver.
Unused
Index of the descriptor that is going to be transmitted next by the
non-real-time Transmit Datapath.
Chapter 23: LAN100 — Ethernet Media Access Controller
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
PNX15xx Series
23-16