Datasheet

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

SDATA

SCLK

SEN

a)EnableSerialReadout(READOUT=1)

A6 A5

A2 A1

D6 D5

D2 D1

SDATA

SCLK

SEN

OVR_SDOUT

(1)

b)ReadContentsofRegister0x43.ThisRegisterHasBeenInitializedwith0x40 (deviceisputintoglobalpower-downmode).

OVR_SDOUT

(2)

0 0 0 0 0

0 0

ADS4122, ADS4125

ADS4142, ADS4145

www.ti.com

SBAS520A –FEBRUARY 2011– REVISED MARCH 2011

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 finctions as OVR (READOUT = 0).

(2) The OVR_SDOUT pin finctions as a serial readout (READOUT = 1).

Figure 13. Serial Readout Timing Diagram

Product Folder Link(s): ADS4122 ADS4125 ADS4142 ADS4145