Altera POS-PHY Level 2 and 3 Compiler - Manual (Page 47)

Chapter 3: Functional Description 3–19
Interface Signals
© November 2009 Altera Corporation POS-PHY Level 2 and 3 Compiler User Guide
Preliminary
Table 3–10 describes the POS-PHY level 3 receive interface.
tenb Link to PHY Transmit write enable. tenb controls the flow of data to the transmit FIFO buffers.
When tenb is high, tdat, tmod, tsop, teop and terr are invalid and are
ignored by the PHY-layer. The tsx signal is valid and is processed by the PHY when
tenb
is high. When tenb is low, tdat, tmod, tsop, teop and terr are valid
and are processed by the PHY-layer. Also, the tsx signal is ignored by the PHY-layer,
when tenb is low.
If you choose Atlantic master for the ‘B’ interface, the tenb signal is combinational.
tsx Link to PHY Transmit start of transfer signal. tsx indicates when the in-band port address is
present on the tdat bus. When tsx is high and tenb is high, the value of
tdat[7:0]
is the address of the transmit FIFO buffer to be selected. Subsequent
data transfers on the tdat bus fill the FIFO buffer specified by this in-band address.
For single-port PHY devices, the tsx signal is optional, because the PHY device
ignores in-band addresses when tenb is high. tsx is valid only when tenb is not
asserted.
dtpa[] PHY to link
Byte-level
mode
Direct transmit packet available. dtpa provides status indication of the
corresponding port in the PHY device. dtpa asserts high when a predefined (user
programmable) minimum number of bytes is available in the transmit FIFO buffer.
dtpa
high does not indicate that the transmit FIFO buffer is full. When dtpa
transitions low, it indicates that its transmit FIFO buffer is full or nearly full (user
programmable). dtpa is required if byte-level transfer mode is supported. dtpa is
updated on the rising edge of tfclk.
tadr[] (1) Link to PHY Transmit address. tadr is used with ptpa to poll the transmit FIFO buffer's packet
available status. When tadr is sampled on the rising edge of tfclk by the PHY, the
polled packet available indication ptpa is updated with the status of the port
specified by the tadr address on the following rising edge of tfclk.
stpa (2) PHY to link Selected PHY transmit packet available. stpa transitions high, when
fifo_threshold
words are available in the transmit FIFO buffer specified by the
in-band address on tdat. When high, stpa indicates that the transmit FIFO buffer is
not full. When stpa transitions low, it indicates that the transmit FIFO buffer is full or
near full (user programmable). stpa always provides status indication for the
selected port of the PHY device to avoid FIFO buffer overflows while polling is
performed. The port which stpa reports is updated on the following rising clock
edge of tfclk after the PHY address on tdat is sampled by the PHY device. stpa
is required if byte-level transfer mode is supported. stpa is updated on the rising
edge of tfclk.
ptpa (1) PHY to link Polled PHY transmit packet available. ptpa transitions high when
fifo_threshold
words are available in the polled transmit FIFO buffer. When
high, ptpa indicates that the transmit FIFO buffer is not full. When ptpa transitions
low, it indicates that the transmit FIFO buffer is full or near full (user programmable).
ptpa
allows the polling of the PHY selected by the tadr address bus. The port that
ptpa reports is updated on the following rising edge of tfclk, after the PHY
address on tadr is sampled by the PHY device. ptpa is required if packet-level
transfer mode is supported. ptpa is updated on the rising edge of tfclk.
Notes to Table 3–9 :
(1) Packet-level mode only
(2) Byte-level mode only
Table 3–9. POS-PHY Level 3 Transmit Interface (Part 2 of 2)
Signal Direction Description