ADS8166: communication of this AD converter

Hello Frank,

Using separate /CS lines, you can share the same SDI, SCLK and SDO lines without a MUX.  However, the /CS line is also used to start the conversion for the ADC.  When connecting SDO lines from 2 or more ADS8166, the /CS lines cannot both be low at the same time, which will prohibit starting conversions at the same time.

If you do not need simultaneous sampling for both ADC's, then sharing all SPI lines except /CS will work.

Is SPI communication a problem if it is switched only by CS?

No Problem as long as simultaneous sampling is not needed.  If needed, then separate SDO lines should be used.  Both ADC's can still share SDI and SCLK lines.

BTW, the bits and channels of figure 72 and table 28 are look like reversed in page 53 of datasheet, which is right?

Thank you for pointing out this datasheet error.  Figure 72 is correct; the channel ID follows the bit position in the register.  Table 28 will need corrected.

Regards,
Keith Nicholas
Precision ADC Applications