3424-XX-UM
ProDAQ 3424 Function Card User Manual
Page 44 of 56
Copyright,
1998-2005 Bustec Production Ltd.
Bit
Access &
Default
Description
15:8
Reserved
7:0
WO
POSTT _NOS
– Post Trigger Number Of Scans
Upper 8 bits (POSTT_NOS [23:16]) of the post trigger number of scans to collect.
5.14. AT_THR_SIGERR
– Analog Trigger Threshold / Signal Error Register
When writing, this register defines value for the threshold 1 and partially for the threshold 2 of the
Analog Trigger
. The thresholds are programmable with 12-bits resolution. As a result, 12 upper bits
of the 24-
bit two’s complement digitised input signal are used when comparing. Values written to
THR1 and THR2 should have two’s complement format of 12-bit length. If no hysteresis is used in
analog triggering, THR2 can be omitted.
When reading, this register returns signal out-of-range error for the given channel.
Bit
Access &
Default
Description
15:12
WO
THR2[3:0]
– Analog Trigger Threshold 2, bits 3 to 0
11:0
R/W
THR1
– Analog Trigger Threshold 1
CHN_RANGE_ERR
– Channel Out-Of-Range Error
Write (bits 11:0) stores THR1
Read (bits 7:0)
1 : signal out-of-range happened for given channel (bit 0 corresponds to first
channel, bit 7 corresponds to last channel)
USAGE
CHN_RANGE_ERR bits show the channel which caused OUTRANGE_ERR
to occur
5.15. AT_CTRL
– Analog Trigger Control Register
This register is used to configure
Analog Trigger
for the selected channel. Set-up AT_THR register
before writing to AT_CTRL register.
Bit
Access &
Default
Description
15:8
WO
THR2[11:4]
– Analog Trigger Threshold 2, bits 11 to 4
7
Reserved
6
WO
COMP_SEL
– Comparison Selection
This bit selects the type of the comparison of the Analog Trigger.
0 : negative slope or ‘less or equal’ selected
1 : positive slope or ‘greater or equal’ selected
5
WO
HYST_EN
– Hysteresis Enable
This bit enables hysteresis of the Analog Trigger.
0 : hysteresis disabled
1 : hysteresis enabled
USAGE
Hysteresis requires two thresholds THR1/2 to set up
If hysteresis is disabled then only THR1 is used
THR1 is compared always first, independently of the direction of the
comparison
For positive slope (or greater than) THR1 has to be not bigger than THR2,
for negative slope (or smaller than) THR1 has to be not smaller than THR2
4
WO
ATMODE_SEL
– Analog Trigger Mode Selection