ADS1294 datasheet(39/88 Pages) TI

39 / 88 page

START

DRDY

SCLK

DIN

DOUT

ADS1298

(Device1)

START

DRDY

SCLK

DIN

DOUT

ADS1294

(Device2)

START

(1)

a)CascadedConfiguration

CLK

INT

GPO0

GPO1

SCLK

MOSI

HostProcessor

MISO

CLK

START

DRDY

SCLK

DIN

DOUT

ADS1298

(Device1)

START

DRDY

SCLK

DIN

DAISY_IN

ADS1294

(Device2)

START

(1)

b)Daisy-ChainConfiguration

CLK

INT

GPO

SCLK

MOSI

HostProcessor

MISO

CLK

DOUT

DAISY_IN

DOUT

DAISY_IN

DO T

SCLK

MSB

216

217

218

MSB

LSB

219

338

LSB

Daaf

romfirstd

ce(

evi

ADS1298)

Daaf

romsecond

de ce(ADS1294)

ADS1294, ADS1294R

ADS1296, ADS1296R

ADS1298, ADS1298R

www.ti.com

SBAS459H

– JANUARY 2010 – REVISED OCTOBER 2011

Cascaded Mode

Figure 45a shows a configuration with two devices cascaded together. One of the devices is an ADS1298 (eight

channels) and the other is an ADS1294 (four channels). Together, they create a system with 12 channels.

DOUT, SCLK, and DIN are shared. Each device has its own chip select. When a device is not selected by the

corresponding CS being driven to logic 1, the DOUT of this device is high-impedance. This structure allows the

other device to take control of the DOUT bus. This configuration method is suitable for the majority of

applications.

Daisy-Chain Mode

Daisy-chain mode is enabled by setting the DAISY_EN bit in the CONFIG1 register. Figure 45b shows the

daisy-chain configuration. In this mode SCLK, DIN, and CS are shared across multiple devices. The DOUT of

one device is hooked up to the DAISY_IN of the other device, thereby creating a chain. One extra SCLK must be

issued between each data set. Also, when using daisy-chain mode, the multiple readback feature is not

available. Short the DAISY_IN pin to digital ground if not used. Figure 2 describes the required timing for the

ADS1298 shown in Figure 46. Data from the ADS1298 appear first on DOUT, followed by a don

’t care bit, and

finally by the status and data words from the ADS1294.

(1) To reduce pin count, set the START pin low and use the START serial command to synchronize and start conversions.

Figure 45. Multiple Device Configurations

Figure 46. Daisy-Chain Timing for Figure 45b

Submit Documentation Feedback

Product Folder Link(s): ADS1294 ADS1294R ADS1296 ADS1296R ADS1298 ADS1298R

ADS1294 Datasheet(PDF) 39 Page - Texas Instruments

ADS1294 Datasheet(HTML) 39 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88

Datasheet Download

Link URL