ADS1282
SCLK
DOUT1
DIN2
ADS1282
SCLK
DOUT2
FPGA or Processor
DOUT1
DIN1
DRDY1
IRQ
SCLK (optional)
SCLK
DOUT2
DIN2
DRDY2
DIN2
IRQ (optional)
DVDD
BYPAS
1.65V to 3.6V
Tie DVDD to BYPAS if
DVDD power is < 2.25V.
Otherwise float BYPAS.
ADS1282
1 F
m
SBAS418I – SEPTEMBER 2007 – REVISED MARCH 2015
9.23 DVDD Power Supply
Serial Interface (continued)
The DVDD supply operates over the range of +1.65V
9.24.1 Serial Clock (SCLK)
to +3.6V. If DVDD is operated at less than 2.25V,
The serial clock (SCLK) is an input that is used to
connect the DVDD pin to the BYPAS pin. If DVDD is
clock data into (DIN) and out of (DOUT) the
greater than or equal to 2.25V, do not connect DVDD
ADS1282. This input is a Schmitt-trigger input that
to the BYPAS pin.
shows this connection.
has a high degree of noise immunity. However, it is
recommended to keep SCLK as clean as possible to
prevent possible glitches from inadvertently shifting
the data.
Data are shifted into DIN on the rising edge of SCLK
and data are shifted out of DOUT on the falling edge
of SCLK. If SCLK is held low for 64 DRDY cycles,
data transfer or commands in progress terminate and
the SPI interface resets. The next SCLK pulse starts
a new communication cycle. This timeout feature can
be used to recover the interface when a transmission
Figure 52. DVDD Power
is interrupted or SCLK inadvertently glitches. SCLK
should remain low when not active.
9.24 Serial Interface
9.24.2 Data Input (DIN)
A serial interface is used to read the conversion data
The data input pin (DIN) is used to input register data
and access the configuration registers. The interface
and commands to the ADS1282. Keep DIN low when
consists of three basic signals: SCLK, DIN, and
reading conversion data in the Read Data Continuous
DOUT. An additional output, DRDY, transitions low in
mode (except when issuing a STOP Read Data
Read Data Continuous mode when data are ready for
Continuous command). Data on DIN are shifted into
retrieval.
shows the connection when
the converter on the rising edge of SCLK.
multiple converters are used.
9.24.3 Data Output (DOUT)
The data output pin (DOUT) is used to output data
from the ADS1282. Data are shifted out on DOUT on
the falling edge of SCLK.
Figure 53. Interface for Multiple Devices
Copyright © 2007–2015, Texas Instruments Incorporated
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