
IBM32NPCXX1EPABBE66
IBM Processor for Network Resources
Preliminary
PHY Bus Interface
Page 26 of 706
pnr261_2io.fm.06
August 14, 2000
FYTCA
1
Input
Transmit Cell Available
When using an external PHY, this indicates that room for a cell
is available in the PHY transmit FIFO. When using the internal
framer, this provides the TX HDLC interface signal,
OFPtxT1Data. When interfacing to POS-PHY, this signal
should be connected to PTPA.
FY0FUL
1
Input
PHY Transmit Full
When using an external PHY, this is asserted low by the PHY
when it can accept no more than four more data transfers
before it is full. This pin should be pulled up to the inactive
state when using a PHY that does not drive it. When using the
internal framer, this provides the TX HDLC interface signal,
OFPtxT1DFrm. When using a POS-PHY interface, this signal
must be connected to STPA
FY0EMP
1
Input
PHY Receive Empty
When using an external PHY, this is asserted low by the PHY
to indicate that in the current cycle there is no valid data for
delivery to the PNR. When the PHY does not drive FY0EMP,
this input should be tied to the inactive state. When using the
internal framer, this signal is not used. When using a POS-
PHY interface, this signal is connected to RVAL.
FYRADR(4-0)
5
Output
PHY Receive Address
When using an external PHY (Cell or POS-PHY based), this
address is used to select and poll up to 31 PHYs on the
receive side. Bits (1-0) are used to select which of the four
PHYs and bit two is used to indicate the null address. When bit
two is B
’
1
’
, bits 1-0 are also
‘
1
’
. When bit 2 is
‘
0
’
, bits 1-0 are
‘
00
’
,
‘
01
’
,
‘
10
’
, or
‘
11
’
.
FYTADR(4-0)
5
Output
PHY Transmit Address
When using an external PHY (Cell or POS-PHY based), this
address is used to select and poll up to 31 PHYs on the trans-
mit side. Bits (1-0) are used to select which of the four PHYs
and bit two is used to indicate the null address. When bit two is
‘
1
’
, bits 1-0 are also
‘
1
’
. When bit 2 is
‘
0
’
, bits 1-0 are
‘
00
’
,
‘
01
’
,
‘
10
’
, or
‘
11
’
.
FYREOP
1
Input
PHY Receive EOP
When using an external POS-PHY, this signal indicates if the
FYRDATA (15-0) contains the last data of a packet. If the
external PHY is not a POS-PHY, this signal should be tied to
GND.
FYTEOP
1
Output
PHY Transmit EOP
When using an external POS-PHY, this signal indicates if the
FYTDATA (15-0) contains the last data of a packet. If the
external PHY is not a POS-PHY, this signal should ignored.
FYRMOD
1
Input
PHY Receive MOD
When using an external POS-PHY, this signal indicates if the
FYRDATA (7-0) contains valid data. If FYRMOD is
‘
1
’
, FYR-
DATA(7-0) is ignored. FYRMOD is only relevant when
FYREOP is
‘
1
’
. A value of
‘
1
’
any other time will be ignored. If a
POS-PHY is not connected, this signal should be tied to GND.
FYTMOD
1
Output
PHY Transmit MOD
When using an external POS-PHY, this signal indicates if the
FYTDATA (7-0) contains valid data. If FYTMOD is
‘
1
’
, FYR-
DATA(7-0) will be ignored. FYTMOD is only driven to a
‘
1
’
when FYTEOP is
‘
1
’
.
Table 9: PHY Bus Signal Descriptions
(Page 2 of 3)
Signal Name
Quantity
Type
Function
Description
Note:
Because some of the PHY transmit I/Os are used for receive framer functions and vice versa, there are some restrictions on how
the interfaces can be used.
1. If the transmit path is using an external PHY and the receive path is using the internal framer, FYTPAR(1) will provide Out of Frame
(OOF) status to the framer and will not be available as a parity output. This is only a concern if the PHY uses a 16-bit data interface
and parity is being used.
2. If the receive path is using an external PHY and the transmit path is using the internal framer, FYRPAR(1) will provide OFPtxLPow
status to the framer and will not be available as a parity input. This is only a concern if the PHY uses a 16-bit data interface.
If the transmit path is using an external PHY and the receive path is using the internal framer, and the external PHY has a 16-bit data
interface, then the receive HDLC interface cannot be used. The three I/O for the RX HDLC interface will instead take on the function of
FYTDAT(15-13).