THS789 Datasheet, PDF (10/34 Pages) Texas Instruments – THS789 Quad-Channel Time Measurement Unit (TMU)

THS789
SLOS776A – SEPTEMBER 2012 – REVISED DECEMBER 2015
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7.4 Device Functional Modes
7.4.1 Serial-Results Interface
The TMU captures time-stamp results and sends them to external logic using an LVDS serial-results port. The
serial-results port consists of a clock signal (RCLK), four strobe signals (Rstrobex) and four data signals
(Rdatax). The Rstrobex signal indicates that a time-stamp data transfer is about to begin for the corresponding
channel.
Table 1 shows the results transfer format and time range.
Table 1. Result Transfer Format and Time Range
RESULT TRANSFER FORMAT
40 bits
TIME RANGE
–7.158 s to 7.158 s
7.4.2 Resister Map Descriptions for All Channels and Central Register
Register
00h
20h
40h
60h
Table 2. Control and Status Register Descriptions for All Channels
Bit
Name
0 En_ChX
1 ChX_IP_EN
2 Pol_X
Function
Enable or disable channel X by powering down the
channel. Time to enable a channel is 200 μs.
Enables or disables the input of channel X. Events are
prevented from entering a channel.
Defines the polarity of the event inputX for the upcoming
timestamp generation.
LogicState
0
1
0
1
0
1
Description
Channel is disabled
Channel is enabled
Input is disabled
Input is enabled
Positive edge
Negative edge
Table 3. Control and Status Register Descriptions for All Channels
Register Bit
Name
0 Reserved
1 Unused
01h
21h
2 Unused
41h
3 Unused
61h
4 Unused
5 Reserved
0 DLL_Lock_X
04h
2 Reserved
24h
44h
3 FIFO_Full_X
64h
4 FIFO_Empty_X
Reserved
Unused
Unused
Unused
Unused
Reserved
Function
Indicates the DLL lock status for channel X.
Reserved
Indicates that the FIFO is full. Timestamps arriving
while FIFO is full are lost.
Indicates that the FIFO is empty.
Logic State
x
x
x
x
x
0
0
1
x
0
1
0
1
Description
DLL locked
DLL not locked
FIFO not full
FIFO full
FIFO not empty
FIFO empty
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