ADS7049-Q1: 4-wire SPI

Hi Brian,

Why do you need 4-wire SPI?  The typical lines are SCLK, /CS, SDO and SDI.  SDI is only used with multi-channel based parts or devices that have a configuration register of some sorts.  The ADS7049 has no need for a DATA INPUT, so there is only a 3-wire SPI interface.  I don't understand why this would be an issue for you.  Can you clarify and provide application details?  Why do you need SDI?

Hello Tom,

Long time no see. Hope you're doing well.

Since Encoder is using ASIC to do the magnetic signal converter and other functions, ASIC is only supporting 4-wire SPI interface. is that making sense? 

Regards

Brian

Doing well Brian,

The ADS7049-Q1 has no need for SDI.  Since there is no need for SDI, you only need 3-wires for control.  What is the ASIC trying to write too?  Send me a note with more details please.

Hello Tom,

Customer mentioned in the Encoder system, there're two devices using 4-wire SPI comm with ASIC.

One is angle sensor MT6835, the other one is ADS794x(for example). The SDI function is needed to handshaking which data in the Sensor or ADC is needed for ASIC. Is it making sense?  

Is there low-cost 4-wire ADC with the sample requirements you recommended?

ASIC SPI pinout:

Angle Sensor: 4-Wire SPI

Regards

Brian

Nope - still don't see the need.  Please set up a call and we can discuss further.