Datasheet

161 2 161 2 1 2
Power-Up
Command
Operation
Command
16
Operation
Command
Power-Down
Active
Invalid Data
Invalid Data
Invalid Data
CS
SCLK
DIN
Power-Down State
(Internal)
DOUT
Power-Up Delay
1 2 16
Operation
Command
Valid Data
1 2 16
Operation
Command
Valid Data
t
d(PWRUP)
Operation Commands Except Power-Down Command
ADS8634
ADS8638
www.ti.com SBAS541A –MAY 2011– REVISED AUGUST 2011
The serial interface is active even during a device power-down state. Commands can be issued via the DIN pin
during a power-down state.
A power-up command (through DIN) is acknowledged on the next CS falling edge and a power-up sequence
initiates. An example of this command is given in Table 7. The device is in an active state after t
d(PWRUP)
and
initiates a valid acquisition in the first data frame (initiated with a CS falling edge) after a power-up delay. The
first valid data are presented in the second data frame after the device attains an active state, as shown in
Figure 84.
Table 7. Power-Up Command Example
RD/
REGISTER ADDRESS WR DATA
PIN Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Any combination from
DIN 0 0 0 0 1 0 X 0 0 X X X X
000 to 110, except 111
Auto/manual sequence W 0 X X X Power-up X
Figure 84. Power-Up Via Register Write
Use only one method (DIN pin or register settings) for power-down/up control. Do not combine these two
methods or the results may be confusing. Do not issue a power-down command through DIN while using the
AL_PD pin. Similarly, do not pull the AL_PD pin low while using the register write method for power-down/up
control.
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