ADS8664 Datasheet, PDF (41/79 Pages) Texas Instruments – 4- and 8-Channel, Single-Supply, SAR ADCs

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ADS8664, ADS8668
SBAS492 – JULY 2015
8.4.2 Device Modes
The ADS8664 and ADS8668 support multiple modes of operation that are software programmable. After
powering up, the device is placed into idle mode and does not perform any function until a command is received
from the user. Table 6 lists all commands to enter the different modes of the device. After power-up, the program
registers wake up with the default values and require appropriate configuration settings before performing any
conversion. The diagram in Figure 95 explains how to switch the device from one mode of operation to another.
/ ^PROG
/ ^PWR_DN
STDBY
RST
STDBY ^{/ PWR_DN / PROG}
RESET
(RST)
Program Registers
are set to default
values
RST NO_OP
IDLE
Device waits for a
valid command to
initiate conversion
MAN_Ch_n
RST
/
AUTO_RST
MAN_Ch_n _{/ AUTO_RST}
NO_OP
MAN_Ch_n
NO_OP
STANDBY
(STDBY)
MAN_Ch_n / AUTO_RST
MANUAL
Channel n
(MAN_Ch_n)
NO_OP
POWER
DOWN
(PWR_DN)
PWR_DN
PROG
PROGRAM
REGISTER
(PROG)
NO_OP
IDLE
STDBY / PWR_DN / PROG
NO_OP
AUTO
Ch. Scan
(AUTO)
Figure 95. State Transition Diagram
NO_OP
AUTO_RST
AUTO Seq.
RESET
(AUTO_RST)
AUTO_RST
8.4.2.1 Continued Operation in the Selected Mode (NO_OP)
Holding the SDI line low continuously (equivalent to writing a 0 to all 16 bits) during device operation continues
device operation in the last selected mode (STDBY, PWR_DN, AUTO_RST, or MAN_Ch_n). In this mode, the
device follows the same settings that are already configured in the program registers.
If a NO_OP condition occurs when the device is performing any read or write operation in the program register
(PROG mode), then the device retains the current settings of the program registers. The device goes back to
IDLE mode and waits for the user to enter a proper command to execute the program register read or write
configuration.
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Product Folder Links: ADS8664 ADS8668
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