Where to find I2C register information for MAX21000+

What's wrong?

Sensor is differential, up to 100psi.
so \$P_{min}\$ is -100psi, \$P_{max}\$ is +100psi.
Total 14 bit (from 0 to 2¹⁴-1),
\$P_{min}\$ is at 10%, so \$OUTPUT_{min}\$ is 1638
\$P_{max}\$ is at 90%, so \$OUTPUT_{max}\$ is 14745

from datasheet: $$ P=\dfrac{(OUTPUT - OUTPUT_{min}) \cdot (P_{max} - P_{min})} {OUTPUT_{max} - OUTPUT_{min}} + OUTPUT_{min}$$

• your first \$OUTPUT\$ value is \$(31 \cdot 256) + 246 = 8182\$
  according to datasheet pressure is:
  $$\dfrac{(8182 - 1638) \cdot (100 - (-100))}{14745 - 1638} - 100 \approx -0.14496071$$
• your second value is \$(34 \cdot 256) + 102 = 8806\$
  $$ \dfrac{(8806 - 1638) \cdot (100 - (-100))} {14745 - 1638} - 100 \approx 9.376669$$
  precision is not so good, but it is still acceptable
• third value: \$(32 \cdot 256) + 30 = 8222\$
  $$\dfrac{(8222 - 1638) \cdot (100 - (-100))} {14745 - 1638} - 100 \approx 0.46540017$$
  something goes wrong, it isn't like 20psi, it is like 0psi.
• fourth value: \$(39 \cdot 256) + 167 = 10151\$
  $$ \dfrac{(10151 - 1638) \cdot (100 - (-100))} {14745 - 1638} - 100 \approx 29.900053$$

The polarity inversion register lets you do a logical NOT on any input line. It doesn't make an input into an output and vice versa.

Operation of this IC seems pretty straightforward:

• Write to register 3 your specific input/output configuration
• If you want the device to do a logical NOT (1->0, 0->1) on any of your input lines, set those bits in register 2
• To read the input lines, read register 0
• To write to the output lines, write to register 1