Hardware Manual

Where not specifically stated, all the interface circuits work at 1.8V CMOS logic levels.
The following table shows the logic level specifications used in the HE910 V2 interface
circuits:
Absolute Maximum Ratings -Not Functional
Parameter
Min
Max
Input level on any digital pin (CMOS 1.8) with respect to ground
-0.3V
2.3V
Operating Range - Interface levels (1.8V CMOS)
Parameter
Min
Max
Input high level
1.5V
2.1V
Input low level
0.0V
0.35V
Output high level
1.35V
1.8V
Output low level
0.0V
0.45V
Current characteristics
Parameter
Typical
Output Current
2mA
Input Current
30uA