WiSnap User Manual 4.41 05282015-ML
Page 55
If you press the WPS button on the access point and then perform a scan, the scan returns a
–A
to indicate the access point is
in WPS active mode.
Scan Showing Access Points in WPS Active Mode
18 Analog Sensor Capability
The WiSnap module has 8 analog sensor inputs that can be driven between 0 to 1.2-V DC. You can sample the analog inputs
and read digital value using the
show q
<
value
> command, where <
value
> is a decimal number representing the channel.
Warning: Driving these inputs above 1.2 V can permanently damage the module.
Input voltage range: 0 - 1.2 V, however the A2D saturates at 400mV. Resolution: 14 bits = 12uV
Sampling frequency: 35us
Accuracy: 5% un-calibrated
The accuracy of each analog sensor reading can be offset by up to 5% due to variation from chip to chip. To improve accuracy it
is recommend using a precision reference voltage on one of the analog inputs to calculate the offset. The offset will be the
same for all analog inputs.
For example:
-
drive precision 200mV reference on analog input 4.
-
read analog input 4 and compute the offset.
If you read 210mv you would know that the offset is +10mv. When you read input 5 you would subtract 10mv from the result.
To read a sensor pin, send the following command:
show q <channel>
Channel is the analog sensor input from 0 to 7. The value for the analog sensor input is measured in microvolts and is returned
as 8xxxxx. The 8 in front is a start marker.