ProDAQ 3424 Function Card User Manual
3424-XX-UM
Copyright,
1998-2005 Bustec Production Ltd.
Page 37 of 56
enabled only on the last receiver in the chain.
6:5
R/W
‘00’
FPCLKO_SEL
– Front Panel Clock Output Selection
These bits select the source of the front panel clock output signal. They have to be
selected only if clock is distributed through the front panel.
00 : FPCLK_OUT disabled
01 : PLL reference clock selected
10 : ADC clock selected
11 : forwards FPCLK_IN to FPCLK_OUT
USAGE
To select the source of the clock when clock is to be distributed to Slaves
through the front panel
4
R/W
0
VREF_ON
– VREF Relay Switch ON
This bit switches the input channels voltage reference between ground and VREF.
0 : Ground selected
1 : VREF selected
USAGE
Used during board’s calibration: ground for offset calibration and VREF for
gain calibration
For the offset calibration process VREFGND_EN of all channels should be
set to ‘1’
For the gain calibration process VREFGND_EN of only one channel at the
time should be set to ‘1’
3
R/W
0
PRET_REJECT
– Pre-trigger Reject
This bit is used to define behaviour of the card in the pre-trigger mode in the case
when trigger came before number of scans defined in the PRET_NOS register was
acquired.
0 : Trigger is accepted before pre-trigger phase finished
1 : Trigger is rejected before pre-trigger phase finished
USAGE
For this bit to have effect,
PRET_EN bit must be set to ‘1’ (pre-trigger mode
enabled)
If trigger can be accepted before PRET_NOS number of scans has been
collected then PRET_NOS register readout gives the value of the missing
scans
2
R/W
0
PRET_EN
– Pre-trigger Enable
This bit is used to enable pre-trigger mode. When pre-trigger mode is selected, data
is stored in the FIFO before trigger happens.
0 : Pre-trigger mode disabled
1 : Pre-trigger mode enabled
USAGE
PRET_NOS register defines number of the samples per channel to be
collected for the pre-trigger. If PRET_NOS is zero then pre-trigger is
disabled even if the bit here is set.
Pre-trigger set-up is valid for any value of the DA_STARTSEL bit. For
immediate start selection the board acquires PRET_NOS scans and then
POSTT_NOS scans
Behaviour of the card in the case when trigger came before number of
scans defined in the PRET_NOS register was acquired is determined by
PRET_REJECT bit. If trigger can be accepted before PRET_NOS number
of scans has been collected then PRET_NOS register readout gives the
number of missing scans
1:0
R/W
‘00’
SYNC_SEL
– SYNC/TRIG Source Selection
These bits select the source of the SYNC/TRIG signal. If the board is MASTER then
it generates the SYNC/TRIG signal internally, otherwise it takes the SYNC/TRIG
from external sources selected by SYNC_SEL.
00 : stack A trigger input (nTRIGI_A) selected
01 : FPSYNC_IO selected
10 : local synchronization sync signal (nLSYNC) selected
11 : reserved