Datasheet

CLK
DRDY
SYNC
t
NDR
t
SYN
t
SCSU
t
CSHD
FSYNC
ValidData
DOUT
SYNC
t
NDR
t
SYN
CLK
t
CSHD
t
SCSU
ADS1274
ADS1278
SBAS367F –JUNE 2007–REVISED FEBRUARY 2011 www.ti.com
Figure 73. Synchronization Timing (SPI Protocol)
Table 11. SPI Protocol
SYMBOL DESCRIPTION MIN TYP MAX UNITS
t
CSHD
CLK to SYNC hold time 10 ns
t
SCSU
SYNC to CLK setup time 5 ns
t
SYN
Synchronize pulse width 1 CLK periods
t
NDR
Time for new data to be ready 129 Conversions (1/f
DATA
)
Figure 74. Synchronization Timing (Frame-Sync Protocol)
Table 12. Frame-Sync Protocol
SYMBOL DESCRIPTION MIN TYP MAX UNITS
t
CSHD
CLK to SYNC hold time 10 ns
t
SCSU
SYNC to CLK setup time 5 ns
t
SYN
Synchronize pulse width 1 CLK periods
t
NDR
Time for new data to be ready
(1)
127 128 Conversions (1/f
DATA
)
(1) If SYNC is asynchronous to the FSYNC clock, then t
NDR
varies from 127 to 128 conversions, starting from the rising edge of SYNC. If
SYNC is made synchronous to the FSYNC clock, then t
NDR
is stable.
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