THS788 Datasheet, PDF (23/43 Pages) Texas Instruments – QUAD-CHANNEL TIME MEASUREMENT UNIT (TMU)

THS788
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Arm_sel3A
1
1
1
1
1
1
1
SLOS616B – MARCH 2010 – REVISED JUNE 2011
Table 18. Channel-C Conditional Arming Definition (continued)
Arm_sel2A
0
0
0
1
1
1
1
Arm_sel1A
0
1
1
0
0
1
1
Arm_sel0A
1
0
1
0
1
0
1
Outcome
ChC will be armed if ChB OR ChD is fully armed.
ChC will be armed if ChA OR ChB OR ChD is fully armed.
Reserved
Reserved
Reserved
Reserved
Reserved
Arm_sel3A
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Arm_sel2A
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Table 19. Channel-D Conditional Arming Definition
Arm_sel1A
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
Arm_sel0A
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Outcome
ChD is armed if ChA is fully armed.
ChD is armed if ChB is fully armed.
ChD is armed if ChC is fully armed.
ChD is armed if ChA AND ChB are fully armed.
ChD is armed if ChA AND ChC are fully armed.
ChD is armed if ChB AND ChC are fully armed.
ChD is armed if ChA AND ChB AND ChC are fully armed.
ChD will be armed if ChA OR ChB is fully armed.
ChD will be armed if ChB OR ChC is fully armed.
ChD will be armed if ChB OR ChC is fully armed.
ChD will be armed if ChA OR ChB OR ChC is fully armed.
Reserved
Reserved
Reserved
Reserved
Reserved
NOTE
When programming individual-channel arming conditions, it is important to avoid
conditions where dependency would cause a lockup situation.
Additional Features
FIFO
Time stamps are written to a FIFO at high speed and read for further processing at a lower speed before being
sent to the result interface. This FIFO is 15 bits deep and 40 bits wide. There are four FIFOs in THS788, one for
each channel. There are two status registers (FIFO_Full_x and FIFO_Empty_x), which are set when a FIFO
reaches its full capacity and when it is empty, respectively.
Serial-Results Interface and ALU
Time stamps are taken and loaded into the FIFO as events occur. Time stamps are mathematically processed by
an arithmetic logic unit (ALU) which calculates the difference between the event and the sync time stamps and
factors in the appropriate calibration value from the calibration register. The ALU operates on the data as it is
read out of the FIFO and sent out through the serial-results interface. The serial-results interface controls the
output of the FIFO. The serial-results interface is programmable in output bit rate and length.
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