HOLT INTEGRATED CIRCUITS

9

Figure 14. 18 bit “Daisy Chained” Configuration Register Write

FUNCTIONAL DESCRIPTION (cont.)

HI-8428-R

CS

SI

SCK

SPI Mode 0

12

3

4

5

67

High Z

8

910 11 12 13 14 15 16

SEL

SO

CR9 CR8 CR7 CR6 CR5 CR4 CR3 CR2

High Z

CR1

NCD

9

NCD

8

NCD

7

NCD

6

NCD

5

NCD

4

NCD

3

NCD

9

New Configuration Register data (NCD9-1) is loaded into Configuration Register on

rising edge

CS

NCDn = New Configuration Register bits to be written to CR

CRn = Old Configuration Register bits read from CR prior to CR write

DCDn = Daisy-chain CR bits from HI-8428-R earlier in chain shifting through the part to be latched in HI-8428-R next in the chain

17 18

NCD

2

NCD

1

DCD

9

DCD

8

DCD

7

DCD

6

DCD

5

DCD

4

DCD

3

DCD

2

DCD

1

DCD

9

DCD

8

DCD

7

DCD

6

DCD

5

DCD

4

DCD

3

DCD

2

DCD

1

Figure 15. Multiple Chip “Daisy-Chain” Connection

24 Channel Sensor Application using HI-8428-R

Host Controller

SEL

SCK

CS

MOSI

HI-8428-R

Device 2

HI-8428-R

Device 3

SI

MISO

SCK

CS

SO

SEL

SCK

CS

HI-8428-R

Device 1

SENSE8

SENSE7

SENSE6

SENSE5

SENSE4

SENSE3

SENSE2

SENSE1

SENSE8

SENSE7

SENSE6

SENSE5

SENSE4

SENSE3

SENSE2

SENSE1

SENSE8

SENSE7

SENSE6

SENSE5

SENSE4

SENSE3

SENSE2

SENSE1

SEL

SEL

SCK

CS

SEL

SCK

CS

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

SENSE8

SENSE7

SENSE6

SENSE5

SENSE4

SENSE3

SENSE2

SENSE1

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ

3kΩ