![Renesas mPD98431 Скачать руководство пользователя страница 36](http://html.mh-extra.com/html/renesas/mpd98431/mpd98431_user-manual_1440626036.webp)
CHAPTER 3 FUNCTIONAL DESCRIPTION
User’s Manual S14054EJ4V0UM
34
(3) Filtering broadcast address
The broadcast packet is stored in the receive FIFO when the ABC bit of the AFR register is set to 1.
(4) Promiscuous mode
The promiscuous mode is set when the PRO bit of the AFR register is set to 1, and the packets of all address
types are stored in the receive FIFO.
(5) Address filtering setting condition
Address filtering is set as follows:
First, set the SRXEN bit of the MACC1 register to 1. If this bit is 0, all the receive packets are ignored and not
received by the receive FIFO. Next, write a station address to the LSA1 and LSA2 registers. Write a
combination of the necessary filtering conditions to the AFR register. To perform conditional multicast packet
reception, a hash table must be set using the HT1 and HT2 registers. When all these settings have been
completed, set the SRXEN bit to 1 to enable packet reception.
3.5.6 Receive FIFO overflow
If the receive FIFO overflows while receive packets are being stored in it, storing of the data is immediately
stopped. If this happens, the packets in the receive FIFO are cleared, and the data received after the overflow
occurred is ignored. The overflow is reported to the host system by the FSVREG register.
3.5.7 Clearing receive FIFO
The host system can clear the contents of the receive FIFO by setting the RXFFLH bit of the MACC3 register to 1.
If this bit is set while receive packets are being stored in the receive FIFO, the packet being received is discarded. If
the preceding receive packet has been already stored in the receive FIFO at this time, this packet is also cleared.
3.6 Full-Duplex Operation
Each port of the
µ
PD98431 can execute full-duplex operation and can transmit and receive packets
simultaneously. If the FULLD bit of the MACC1 register is set to 1, the full-duplex operation is enabled. In this case,
the COLn and CRSn signals are ignored. If the setting of the SRXEN bit of the MACC1 register is changed while the
CRSn signal is high, the new value of the SRXEN bit becomes valid after the CRSn signal has gone low, regardless
of the setting of the FULLD bit.
3.7 System Bus Interfaces
The
µ
PD98431 has a FIFO bus interface and a register bus interface to interface the host system. The FIFO bus
interface is used to transfer transmit/receive data between the internal FIFOs of the
µ
PD98431 and host system. The
register bus interface is used to access the internal registers and statistics counters of the
µ
PD98431.
3.7.1 FIFO bus interface
The
µ
PD98431 has two FIFO bus interface modes: 32-bit dual bus mode and 64-bit single bus mode. In the 32-
bit dual bus mode, a 32-bit transmit data bus and a 32-bit receive data bus are used so that transmit or receive data
can be transferred unidirectionally. In the 64-bits single bus mode, a 64-bit bidirectional data bus is used to transfer
transmit/receive data. These bus modes are selected depending on the setting of the MISCR register.
The data transfer rate of the FIFO bus interface is up to 66 MHz in both the bus modes.
Содержание mPD98431
Страница 4: ...User s Manual S14054EJ4V0UM 2 MEMO ...