IXF1104
5.2.2.8.2Parity
The IXF1104 can be odd or even (the IXF1104 defaults to odd) when calculating parity on the data bus. This can be changed to accommodate even parity if desired, and can be set for transmit and receive ports independently. The RX and TX parity sense bits have a direct relationship to the port parity in SPHY mode.
The per port RX parity is set in the “SPI3 Receive Configuration ($0x701)" and the per port TX Parity is set in the “SPI3 Transmit and Global Configuration ($0x700)".
5.2.2.9SPI3 Flow Control
The SPI3 packet interface supports transmit and receive data transfers at clock rates independent of the line bit rate. As a result, the IXF1104 supports packet rate decoupling using internal FIFOs. These FIFOs are 10 KB per port in the transmit direction (egress from the IXF1104 to the line interfaces) and 32 KB per port in the receive direction (ingress to the IXF1104 from the line interfaces).
Control signals are provided to the network processor and the IXF1104 to allow either one to exercise flow control. Since the bus interface is
5.2.2.9.1RX SPI3 Flow Control
In the receive direction, when the IXF1104 has stored an
RENB_0:3
RENB_0:3 controls the flow of data from the IXF1104 RX FIFOs. In SPHY mode, there is a dedicated RENB for each port. In MPHY mode, RENB_0 is used as the global signal covering all ports. When RENB is sampled Low, the network processor can accept data. A read is performed from the RX FIFO and the RDAT, RPRTY, RMOD[1:0], RSOP, REOP, RERR, RSX, and RVAL signals are updated on the following rising edge of RFCLK.
RENB can be asserted High by the Network Processor at any time if it is unable to accept any more data. When the RENB is sampled High by the IXF1104, a read of the RX FIFO is not performed, and the RDAT, RPRTY, RMOD[1:0], RSOP, REOP, RERR, RSX and RVAL signals remain unchanged on the following rising edge of RFCLK.
5.2.2.9.2TX SPI3 Flow Control
In the transmit direction, when the IXF1104 has space for some predefined number of bytes in its transmit FIFO, it informs the Network Processor device by asserting one of the Transmit Packet Available (TPA) signals. The Network Processor device writes the
90 | Datasheet |
Document Number: 278757
Revision Number: 007
Revision Date: March 25, 2004