I/O support
Monitor I/O lines
Digi XBee® 3 802.15.4 RF Module User Guide
92
Function
Micro Pin
SMT Pin
TH Pin
AT Command
PWM0
7
7
6
P0 (DIO10/RSSI/PWM0 Configuration)
PWM1
8
8
7
specifies the analog reference voltage used for the 10-bit ADCs. Analog
sample data is represented as a 2-byte value. For a 10-bit ADC, the acceptable range is from
0x0000
to
0x03FF
. To convert this value to a useful voltage level, apply the following formula:
ADC / 1023 (vREF) = Voltage
Note
ADCs sampled through MicroPython will have 12-bit resolution.
Example
An ADC value received is 0x01AE; to convert this into a voltage the hexadecimal value is first converted
to decimal (0x01AE = 430). Using the default
AV
reference of 1.25 V, apply the formula as follows:
430 / 1023 (1.25 V) = 525 mV
Monitor I/O lines
You can monitor pins you configure as digital input, digital output, or analog input and generate I/O
sample data. If you do not define inputs or outputs, no sample data is generated.
Typically, I/O samples are generated by configuring the device to sample I/O pins periodically (based
on a timer) or when a change is detected on one or more digital pins. These samples are always sent
over the air to the destination address specified with
.
You can also gather sample data using on-demand sampling, which allows you to interrogate the state
of the device's I/O pins by issuing an AT command. You can do this on either a local or remote
device via an AT command request.
The three methods to generate sample data are:
n
Periodic sample (
)
l
Periodic sampling based on a timer
l
Samples are taken immediately upon wake (excluding pin sleep)
l
Sample data is sent to
DH
+
DL
destination address
l
Can be used with line passing
l
Requires API mode on receiver
n
Change detect (
l
Samples are generated when the state of specified digital input pin(s) change
l
Sample data is sent to
DH
+
DL
destination address
l
Can be used with line passing
l
Requires API mode on receiver
