Altera POS-PHY Level 4 IP Core - Manual (Page 25)

Chapter 3: Parameter Settings 3–5
Basic Parameters
December 2014 Altera Corporation POS-PHY Level 4 IP Core User Guide
Atlantic FIFO Buffer Clock
The Atlantic FIFO buffer clock sets the clock mode for the Atlantic FIFO buffers. Two
choices are available: Single or Multiple.
With a single Atlantic FIFO buffer clock, the Atlantic FIFO buffers are instantiated as
single clock domain buffers that do not include any clock crossing logic and therefore
consume fewer logic resources.
With a multiple Atlantic FIFO buffer clocks, the Atlantic FIFO buffers are instantiated
as multiple clock domain buffers. Each buffer has two independently operated clock
inputs, thus each Atlantic interface has a separate clock input. Multiple Atlantic FIFO
buffer clocks consume more logic resources.
Atlantic Interface Width
The Atlantic interface width includes 32, 64, or 128 bits, and depends on the internal
data path width.
Table 3–2 shows the Atlantic data widths supported for each internal
data path width.
1
For the individual buffers mode, all buffers have the same data path width.
The Status channel clock edge determines on which clock edge—positive (rising),
negative (falling), or programmable—the 2-bit status channel is transmitted (by the
receiver IP core) in reference to the tsclk (for the transmitter) or rsclk (for the
receiver) pin. When you turn on Programmable Edge, an input pin,
(ctl_ts_statedge for the transmitter; ctl_rs_statedge for the receiver), controls the
status channel clocking edge statically at reset.
1
To ensure proper sampling of the status information, you should typically set this
parameter to be the opposite of the sampling clock edge on the adjacent device.
For the Status channel I/O standard, either LVTTL or LVDS, select LVDS to
implement the optional lower bandwidth LVDS status operation (refer to the OIF-
SPI4-02.1 specification).
Table 3–2. Atlantic Interface Data Width Limitations
Internal Data Path Width (Bits) Supported Atlantic Data Width (Bits)
128 128
64 64 and 128
32 32 and 64