ST269 -vs- ST168 ADC timing

[gmeyer]

Posted on September 25, 2003 at 14:04

ST269 -vs- ST168 ADC timing

[gmeyer]

Posted on September 03, 2003 at 21:09

The document AN1313 states that there isn't a software difference between the anlog to digital converters of the ST269 and ST168 but when I look at the data sheets, the tcc value is off by a factor of two for a given ADSTC setting.

Wouldn't we have to take this into account when porting to the ST269 so that we maintain the same sample time?

[charles239955_st]

Posted on September 25, 2003 at 14:04

In fact the total conversion time is the same. It is a ''documentation'' trick. 2 timings are defined depending on the doc you will have: either tsc (sample clock) or ts (sample time) with ts = 2x tsc.

Then sometimes the formula for the total conversion time is: either tc = 14 tcc + ts +4 TCL either tc = 14 tcc + 2 tsc + 4 TCL In summary, for both devices the formula is: tc = 14 tcc + 2 tsc + 4 TCL and tsc = tcc for ADSTC = 00 tsc = 2 tcc for ADSTC = 01 tsc = 4 tcc for ADSTC = 10 tsc = 8 tcc for ADSTC = 11