
PCI930
3-TO-1 ZOOMED VIDEO SWITCH
SCPS018B – OCTOBER 1997 – REVISED DECEMBER 1997
6
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
Table 3. ZV Switch Control and Status Terminals
TERMINAL
TYPE
FUNCTION
NAME
NO.
TYPE
FUNCTION
RESET
116
I
Chip reset. When asserted (driven low), the chip three-states all outputs. In addition, the PCI930
checks for a pullup resistor on the A/B STAT pin as denoted under ZV_xx terminal function.
A/B_STAT
48
I
PC Card ZV (Socket 0 or 1) active. This input indicates that either the A or B source from the PC Card
controller is active. This signal is used with A/B_SEL to determine which socket ZV source drives the
ZV_xx outputs. The A or B source can be passed to ZV_xx if the C source is either of lower precedence,
or is not sourcing valid ZV data, as indicated by the C_STAT signal.
A/B_SEL
49
I
Socket A/B select. When this pin and A/B_STAT are high, the PC Card socket A ZV data is valid. When
this pin is low, and the A/B_STAT input is high, the PC Card socket B ZV data is valid. This input has
no meaning if the A/B_STAT input is low.
C_STAT
50
I
C source status. When this input is high, the ZV source from interface C is valid, and can be driven
to the ZV_xx outputs. The C source can be passed to ZV_xx if the A and B sources are either of lower
precedence, or A or B is not sourcing valid ZV data.
ZV_OE
114
I
ZV output I/F enable. When this terminal is low, the ZV switch drives the ZV_xx terminals.
ZV_STAT
113
O
ZV output status. This terminal is driven high when the ZV switch drives the ZV_xx terminals.
ZV_xx State
N/A
When a pullup resistor is present on the A/B_STAT pin during RESET, then the ZV_xx interface is
three-stated if the ZV_xx interface is inactive. During the default state, no pullup resistor, a reset drives
the ZV_xx interface to a logic low state when inactive.