Datasheet

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1
SDATA
SCLK
SEN
a)EnableSerialReadout(READOUT=1)
A7
A6 A5
A4
A3
A2 A1
A0
D7
D6 D5
D4
D3
D2 D1
D0
SDATA
SCLK
SEN
OVR_SDOUT
(1)
b)ReadContentsofRegister0x43.ThisRegisterHasBeenInitializedwith0x40 (deviceisputinglobalpower-downmode).
OVR_SDOUT
(2)
1
0 0 0 0 0
0 0
RegisterAddressA[7:0]=0x00 RegisterDataD[7:0]=0x01
RegisterAddressA[7:0]=0x43
RegisterDataD[7:0]=XX(don’tcare)
ADS4126 , ADS4129
ADS4146 , ADS4149
SBAS483G – NOVEMBER 2009–REVISED JANUARY 2011 www.ti.com
Serial Register Readout
The serial register readout function allows the contents of the internal registers to be read back on the
OVR_SDOUT pin. This readback may be useful as a diagnostic check to verify the serial interface
communication between the external controller and the ADC.
After power-up and device reset, the OVR_SDOUT pin functions as an over-range indicator pin by default. When
the readout mode is enabled, OVR_SDOUT outputs the contents of the selected register serially:
1. Set the READOUT register bit to '1'. This setting puts the device in serial readout mode and disables any
further writes to the internal registers except the register at address 0. Note that the READOUT bit itself is
also located in register 0. The device can exit readout mode by writing READOUT = 0. Only the contents of
the register at address 0 cannot be read in the register readout mode.
2. Initiate a serial interface cycle specifying the address of the register (A7 to A0) whose content has to be
read.
3. The device serially outputs the contents (D7 to D0) of the selected register on the OVR_SDOUT pin.
4. The external controller can latch the contents at the falling edge of SCLK.
5. To exit the serial readout mode, the reset register bit READOUT = 0 enables writes into all registers of the
device. At this point, the OVR_SDOUT pin becomes an over-range indicator pin.
(1) The OVR_SDOUT pin functions as OVR (READOUT = 0).
(2) The OVR_SDOUT pin functions as a serial readout (READOUT = 1).
Figure 13. Serial Readout Timing Diagram
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