
29
2.5.1.3
High-Speed Data Interface (continued)
NAME
PDT PIN NO.
PGE PIN NO.
I/O
DESCRIPTION
HSDIB_CLK
123
137
I
HSDI port B clock. (Data is clocked on the rising clock
edge.) Max throughput in byte mode is 27 Mbytes/sec.
HSDIB_SYNCZ
125
139
I/O
HSDI port B synchronization signal. Used to determine
data packet boundaries. In 1394 transmit mode, the
external host device drives the signal, marking the
beginning or end of a data block. In 1394 receive mode,
the ceLynx drives the pin, signaling the beginning or end
of a data block. The exact operation of the
HSDIB_SYNCZ depends on the synchronization mode.
HSDIB_SYNCZ polarity is programmable and defaults
to
active high.
In default HSDIB configuration, this signal
is not used.
HSDIA_SYNCZ
23
25
I/O
HSDI port A synchronization signal. Used to determine
data packet boundaries. In 1394 transmit mode, the
external host device drives the signal, marking the
beginning or end of a data block. In 1394 receive mode,
the ceLynx drives the pin, signaling the beginning or end
of a data block. The exact operation of the
HSDIA_SYNCZ depends on the synchronization mode.
HSDIA_SYNCZ polarity is programmable and defaults
to
active high.
In default HSDIA configuration, this signal
is not used.
HSDIA_RWZ
20
22
I
HSDI port A read/write signal. Used to indicate either a
host read or a host write transaction to the HSDIA port.
HSDIA_R/WZ polarity is programmable and defaults to
active high
for read operations and
active low
for write
operations.
HSDIB_RWZ
120
134
I
HSDI port B read/write signal. Used to indicate either a
host read or a host write transaction to the HSDIB port.
HSDIB_R/WZ polarity is programmable and defaults to
active high
for read operations and
active low
for write
operations.
HSDIA_AVZ
22
24
O
HSDI port A data available. Used during 1394 receive
operations. Indicates when a packet of data is available
in the selected receive buffer (as indicated by
HSDIA_A[2:0]).
HSDIA_AVZ polarity is programmable and defaults to
active high
.
HSDIB_AVZ
126
140
O
HSDI port B data available. Used during 1394 receive
operations. Indicates when a packet of data is available
in the selected receive buffer (as indicated by
HSDIB_A[2:0]).
HSDIB_AVZ polarity is programmable and defaults to
active high
.