ADS1259
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SBAS424C –JUNE 2009–REVISED MARCH 2010
Data Read Operation in Stop Continuous Mode
As shown in Figure 60, after sending the RDATA
command the data are shifted out on DOUT on the
rising edges of SCLK. The MSB is clocked out on the
first rising edge of SCLK. In Gate Control mode,
DRDY returns to high on the first falling edge of
SCLK. In Pulse Control mode, DRDY remains low
until a new conversion is started.
In Stop Read Data Continuous mode, a read data
command (RDATA) must be sent for each new data
read operation. New conversion data are ready when
DRDY falls low or the DRDY register bit transitions
low. The data read operation may then occur. The
read data command must be sent at least 20 fCLK
cycles before the DRDY falling edge or the data are
incorrect. Do not the read data command during this
time.
The conversion data consist of three or four bytes
(MSB first), depending on whether the checksum byte
is included. The data may be read multiple times by
continuing to shift the data.
Data Ready
Next Data Ready
DRDY(1)
(3)
tUPDATE
CS(2)
1
9
17
25
33
41
SCLK
DOUT
DIN(7)
Hi-Z
CHECKSUM(5)
DATA MSB(6)
(4)
DATA MSB
DATA MID
DATA LSB
012h(8)
(1) In Gate Control mode, DRDY returns to high on the first falling edge of SCLK. In Pulse Control mode, DRDY remains low until the next
conversion is started. The DRDY pin or DRDY register bit can also be polled to determine when data are ready.
(2) CS may be held low.
(3) tUPDATE = 20/fCLK. Do not issue the Read Data opcode during this time.
(4) During this interval, DOUT does not follow DRDY (stop continuous mode).
(5) Optional conversion data checksum.
(6) Optional repeat of previous conversion data.
(7) DIN data are latched on the falling edge of SCLK. Data are output on the rising edges of SCLK.
(8) Read Data command = 012h.
Figure 60. Data Read Operation in STOP Continuous Mode
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