THS788 Datasheet, PDF (32/43 Pages) Texas Instruments – QUAD-CHANNEL TIME MEASUREMENT UNIT (TMU)

THS788
SLOS616B – MARCH 2010 – REVISED JUNE 2011
www.ti.com
SYNC
EVENT
Max Freq.
200 MHz
200 ps Min PW
T1
T2
T3
T0430-01
Figure 13. Time-Measurement Example at Maximum Retrigger Rate and Minimum Pulse Duration
The TH788 is capable of making time measurements using any combination of rising-falling edge between Event
and SYNC. The example in Figure 13 uses rising edges only to trigger the time measurement. Table 23
describes what registers bits must be programmed to achieve the desired combination. Registers to be
programmed are 00h, 20h, 40h, and 60h for event channels and 80h for the sync channel. The examples in
Figure 14 illustrate the other three combinations. It is worth noting that all the channels can be programmed
individually with respect to the sync channel.
Table 23. Trigger Polarity Programmability
Register Bits
SYNC_TS_Pol
0
0
1
1
Pol_X
0
1
0
1
Trigger Polarity from
Sync to Event
Pos to Pos
Pos to Neg
Neg to Pos
Neg to Neg
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