LMH0366

RATE1

1

2

3

4

5

6

DAP

Differential

Data Input

ENABLE

27 MHz

39 pF

39 pF

Data Output 0

Data Output 1 or

Clock Output

VCC

56 nF

LOCK_ DETECT

MUTE

BYPASS

RATE1

RATE0

SCO_EN

SDI

SDI

BYPASS

ENABLE

MUTE

13

14

15

16

17

18

SDO1

SDO1

SDO0

SDO0

VCC

SD/HD

SD/HD

0x7F

0x5A

1

MOSI

(host)

R/W

Addr

Data

0x7F

0x5A

1

R/W

Addr

Data

0x7F

0x5A

1

R/W

Addr

Data

XX

X

XX

XX

X

XX

XX

X

MISO

(host)

XX

0x7F

0x5A

1

R/W

Addr

Data

0x7F

1

0x5A

LMH0366

www.ti.com

SNAS585D – APRIL 2012 – REVISED APRIL 2013

SPI Daisy-Chain Length Detection

A useful operation for the host may be to detect the length of the daisy-chain. This is a simple matter of shifting

in a series of dummy reads with a known data value (such as 0x5A). For an SPI daisy-chain of N LMH0366

devices, the known data value will appear on the host's MISO pin after N+1 writes. Assuming a daisy-chain of

three LMH0366 devices, the result of this operation is shown in Figure 10.

Figure 10. SPI Daisy-Chain Length Detection

APPLICATION INFORMATION

Application Circuit (Pin Mode)

Figure 11 shows the typical application circuit for the LMH0366 in pin mode.

Figure 11. Application Circuit (Pin Mode)

Copyright © 2012–2013, Texas Instruments Incorporated

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