LTC2452
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2452fd
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applicaTions inForMaTion
2) After the 16th bit is read, the user can choose one of
two ways to begin a new conversion. First, one can
pull CS high (CS = ↑). Second, one can use a high-low
transition on SCK (SCK = ↓).
3) At any time during the Data Output state, pulling CS
high (CS = ↑) causes the part to leave the I/O state,
abort the output and begin a new conversion.
4) When SCK = HIGH, it is possible to monitor the conver
-
sion status
by pulling CS low
and watching for SDO to
go low. This feature is available only in the idle-high
(CPOL = 1) mode.
Serial Clock Idle-High (CPOL = 1) Examples
In Figure 6, following a conversion cycle the LTC2452
automatically enters the low power sleep mode. The user
can monitor the conversion status at convenient intervals
using CS and SDO.
Pulling CS LOW while SCK is HIGH tests whether or not
the chip is in the CONVERT state. While in the CONVERT
state, SDO is HIGH while CS is LOW. In the SLEEP state,
SDO is LOW while CS is LOW. These tests are not required
operational steps but may be useful for some applications.
When the data
is available, the user applies 16 clock cycles
to transfer the result. The CS rising edge is then used to
initiate a new conversion.
The operation example of Figure 7 is identical to that of
Figure 6, except the new conversion cycle is triggered by
the falling edge of the serial clock (SCK). A 17th clock
pulse is used to trigger a new conversion cycle.
Serial Clock Idle-Low (CPOL = 0) Examples
In Figure 8, following a conversion cycle the LTC2452
automatically enters the low-power sleep state. The user
determines data availability (and the end of conversion)
Figure 6. Idle-High (CPOL = 1) Serial Clock Operation Example.
The Rising Edge of CS Starts a New Conversion
Figure 7. Idle-High (CPOL = 1) Clock Operation Example.
A 17th Clock Pulse is Used to Trigger a New Conversion Cycle
D
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clk
1
clk
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clk
3
clk
4
clk
15
clk
16
D
14
D
13
D
12
D
2
D
1
D
0
SD0
SCK
CONVERT CONVERTSLEEP DATA OUTPUT
2452 F06
CS
D
15
D
14
D
13
D
12
D
2
D
1
D
0
SD0
clk
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clk
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clk
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clk
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clk
15
clk
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clk
17
SCK
CONVERT CONVERTSLEEP DATA OUTPUT
2452 F07
CS
