General Purpose Flash Memory; Access General Purpose Flash Memory - Digi XBee SX 868 User Manual

Advanced application features
Command Description
D2 DIO2/AD2
D3 DIO3/AD3
T3 DIO3 Timeout
In the example, both devices have I/O Line Passing enabled with appropriate inputs and outputs
configured. The IA parameter determines which device on the network is allowed to affect the
device's outputs.
Device A takes a periodic sample of all I/O lines every two seconds and transmits it as a unicast
transmission to the address defined by DH and DL (in this case, Device B). Device B does not
periodically sample, instead it monitors DIO3 for a binary change. When it detects a change on that
pin, it generates a sample and transmits it as a broadcast to all devices on the network.
When Device B receives a sample packet from Device A:
DIO2 on Device B outputs the state of DIO2 from Device A.
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PWM1 outputs a duty cycle equivalent to the analog voltage read on AD1 of Device A.
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A PWM timeout has been set to three seconds; if no sample is received, PWM1 returns to 0 V
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after this period.
When Device A receives a sample packet from Device B:
DIO3 on Device A outputs the state of DIO3 from Device B.
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A DIO3 timeout has been set to 10 seconds; if no sample is received, DIO3 reverts to a HIGH
n
state after this period.
Note By default, all Digital I/O lines have internal pull-up resistors enabled with the PR command. This
causes inputs to float high. You can use the PD command to change the direction of the internal pull-
up/down resistors. The XBee SX 868 RF Module uses an internal reference voltage of 2.5 V for ADC
lines, but you can use the AV command to set it to 1.25 VDC.

General Purpose Flash Memory

XBee SX 868 RF Modules provide 61 2048-byte blocks of flash memory that an application can read
and write to. This memory provides a non-volatile data storage area that an application uses for many
purposes. Some common uses of this data storage include:
Storing logged sensor data
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Buffering firmware update data for a host microcontroller
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Storing and retrieving data tables needed for calculations performed by a host microcontroller
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The General Purpose Memory (GPM) is also used to store a firmware update file for over-the-air
firmware updates of the device itself.

Access General Purpose Flash Memory

To access the GPM of a target node locally or over-the-air, send commands to the MEMORY_ACCESS
cluster ID (0x23) on the DIGI_DEVICE endpoint (0xE6) of the target node using explicit API frames. For
a description of Explicit API frames, see
To issue a GPM command, format the payload of an explicit API frame as follows:
XBee® SX 868 RF Module User Guide
Device A
3: Digital input
5: Digital output, HIGH
0x64 (10 seconds)
Operate in API mode.
General Purpose Flash Memory
Device B
5: Digital output, HIGH
3: Digital input
N/A
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