NCV7728DPAR2G datasheet(18/27 Pages) ONSEMI

18 / 27 page

NCV7728

www.onsemi.com

MCU

NCV7728

16 Bit SPI

CSB

SCLK

CSB

SCLK

n*8 Bit SPI Device

(ie n=2; 16 bits)

CSB

SCLK

Device1

Device2

8 bits

Command Bits for the Device 2

Previous Diagnostic Bits from Device2

Command Bits for Device 1

Previous Diagnostic Bits From Device1

Figure 16. Serial Daisy Chain

If Device 2 is a 16 bit IC, then a total of 32 bits must be

generated from the MCU for a complete transport of data in

the system. Monitoring of all the devices in the serial chain

must be employed on a system level architecture. Thus,

pre−cautious measure should be taken to avoid situations

where not enough frames were sent to the devices, but the

frames transmitted did not violate the internal frame

detection counters. For these scenarios, invalid data is

accepted by NCV7728 and possibly by other devices on the

chain depending on their frame detection design. The data

shifted in will be transferred to the data registers of the

devices on the beginning of the chain and the devices at the

end of the chain will get the previous diagnostic data of the

preceding devices.

NCV7728DPAR2G Datasheet(PDF) 18 Page - ON Semiconductor