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IBM2520L8767
IBM Processor for ATM Resources
ATM PHY Bus Interface
Page 30 of 553
atmrm.chapt02.01
08/27/99
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 assume the OOF
function and 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 assume the OFPtxLPow
function and not be available as a parity input. This is only a concern if the PHY uses a 16-bit data interface.
3. 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).
1
FYTCA
Input
Transmit Cell Available.
When using an external PHY, this indicates that a cell is avail-
able in the PHY transmit FIFO. When using the internal framer,
this provides the TX HDLC interface signal, OFPtxT1Data.
When interfacing to IBM ATM-TC, it should be connected to
+TLoad.
1
FYFUL
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 inter-
nal framer, this provides the TX HDLC interface signal,
OFPtxT1DFrm.
1
FYEMP
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 IBM2520L8767. 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.
1
FYTSDATP/N
Input
SERDES Transmit Data
(Differential).
When using the internal framr and the internal serdes, these
signals provide the serial transmit data stream.
1
FYTSCLKP/N
Input
SERDES Transmit Clock
(Differential).
When using the internal framr and the internal serdes, the ref-
erence 155.52MHz clock is supplied on these signals. When
not in use, these should be tied to (TBD).
1
FYRSDATP/N
Input
SERDES Receive Data
(Differential).
When using the internal framr and the internal serdes, the
recovered receive data is supplied on these signals. When not
in use, these should be tied to (TBD).
1
FYRSCLKP/N
Input
SERDES Receive Clock
(Differential).
When using the internal framr and the internal serdes, the
recovered 155.52MHz clock is supplied on these signals.
When not in use, these should be tied to (TBD).
1
FYDTCT
Input
PHY Carrier Detect.
When using an external PHY, the PHY uses this signal to indi-
cate carrier detect. When using the internal framer, this signal
provides the deserializer lock detect signal, ELockDet, from the
deserializer.
1
FYDISCRD
Input
PHY Cell Discard.
When using an external PHY, this signal causes the current
cell being received to be discarded. In this case it should only
be asserted for the duration of one of the 53 bytes of the ATM
cell. When using the internal framer, this signal provides the
optical/electrical module Loss-Of-Signal indication, LossSig.
1
FYSETCLP
Input
PHY CLP Bit Set
When HIGH, causes the current cell being received to have its
CLP bit set to 1. This signal should only be asserted for the
duration of one of the 48 data bytes of the ATM cell.
PHY Bus Pin Descriptions
(Page 2 of 2)
Quantity
Pin Name
Input/Output
Pin Function
Pin Description