Datasheet

SCLK
DOUT Don'tCare DataByte1(MSB) DateByte4(LSB)
DRDY
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 33 34 35 36 37 38 39 40
DIN CommandByte(00010010)
t
DR
t
DDPD
Standby PerformingOne-ShotConversion Standby
STANDBY
ADS1281Status
DRDY
DIN
DOUT
WAKEUP
(1)
STANDBY
Settled
Data
ADS1281
SBAS378D –AUGUST 2007–REVISED JUNE 2010 www.ti.com
Read Data By Command
ONE-SHOT OPERATION
The Read Data Continuous mode is stopped by the
The ADS1281 can perform very power-efficient,
SDATAC command. In this mode, conversion data
one-shot conversions using the STANDBY command
are read by command. In the Read Data By
while under software control. Figure 49 shows this
Command mode, a read data command must be sent
sequence. First, issue the STANDBY command to set
to the device for each data conversion (as shown in
the Standby mode.
Figure 48). When the read data command is received
When ready to make a measurement, issue the
(on the eighth SCLK rising edge), data are available
WAKEUP command. Monitor DRDY; when it goes
to read only when DRDY goes low (t
DR
). When DRDY
low, the fully settled conversion data are ready and
goes low, conversion data appear on DOUT. The
may be read directly in Read Data Continuous mode.
data may be read on the rising edge of SCLK.
Afterwards, issue another STANDBY command.
When ready for the next measurement, repeat the
cycle starting with another WAKEUP command.
Figure 48. Read Data By Command, RDATA (t
DDPD
timing is given in Table 15)
Table 16. Read Data Timing for Figure 48
PARAMETER DESCRIPTION MIN TYP MAX UNITS
t
DR
Time for new data after data read command 0 1 f
DATA
(1) See Figure 41 and Table 13 for time to new data.
Figure 49. One-Shot Conversions Using the STANDBY Command
26 Submit Documentation Feedback Copyright © 2007–2010, Texas Instruments Incorporated
Product Folder Link(s): ADS1281