18 GBX24 VME 24 Port Gigabit Ethernet Switch
Publication No. GBX24-0HH/2
3.3 Link Descriptions
NOTE
Ordinary operation requires no jumpers to be fitted.
3.3.1
JTAG Mode Select (J12)
This
link
can
be
used
to
select
the
JTAG
mode,
as
follows:
Table 3-1 J12 Functionality
Setting Meaning
Pins 1 and pin 2 linked Reserved
Pins 2 and pin 3 linked PLD programming via J13 header
No jumper fitted
JTAG disabled
3.3.2
Board Configuration (J15)
This
header
replicates
functionality
available
at
the
P2
connector.
Table 3-2 J15 Functionality
Pins Function Description
1 and 2
Reserved
3 and 4
BIT Fast Start Fitting a jumper forces the GBX24 to start quickly by bypassing BIT
5 and 6
Recovery
Fitting a jumper enables reprogramming of the board
7 and 8
Reset
Fitting a jumper enables a Reset to be applied to the board remotely without
affecting any other boards in the system
9 and 10
Slave
When the GBX24 is used in a two-board configuration as a 48-port switch, this
selects whether the board is the Master (jumper fitted) or Slave (no jumper fitted)
11 and 12 Reserved
CAUTION
The link settings on pins 3 & 4, 5 & 6 and 9 & 10 are only sampled during power-up/reset. Do not
change the link setting while the board is powered.