AnsweredAssumed Answered

ADIS162xx/3xx/4xx minimum data period is confusing

Question asked by BillW on Jan 23, 2014
Latest reply on Feb 20, 2014 by BillW

In datasheet for ADIS16265/ADIS16364 etc, there is a spec for minimum data period called tDATARATE.  For example, on ADIS16265 it is 32microseconds in normal mode.  So I think that says that I must have a minimum of 32us between CS falling edges.  Thus limiting the data rate to only sending/reading 16-bits every 32us.  What am I missing?

 

See below your example of a proper test.  I don't see anything that makes sure we wait 32us between CS falling edges.

 

SPI Test Pattern/Example

All ADIS162xx/3xx/4xx devices offer a product identification register (PROD_ID), which contains the 16-bit binary representation of the product's part number.  In the case of the ADIS16407, the PROD_ID = 0x4017 (16,407) and is located at register address 0x56 and 0x57.  Set DIN = 0x5600 to read this register. Reading this register, in a repeating pattern, enables inspection for all of the listed SPI communication issues. Here is an example (psuedo code) for a test loop, which reads PROD_ID in a repeating pattern. Starting with the second loop, DOUT should be equal to 0x4017, every time. 

Set CS = 1;  // Standard for no communication

Delay > 10us  // Make sure that Tstall time is managed

Start Loop

  Set CS = 0;  // select the device, good idea to trigger a scope on this edge

  DIN = 0x5600;

  Read DOUT  // Note that the ADIS16xxx devices support full duplex operation, so this may be combined with DIN = 0x5600 step

  Set CS = 1; // release the device

  Delay > 10us  // manage the Tstall time requirement

End

Outcomes