XBEE Range Check
Harris Junaid.
0
replies
Device Addressing
identifiednby their unique 64-bit adresses or a userconfigurable
ASCII string identifier
- address read using SH and SL command
- identifier string set using NI command
AT Firmware Device Addressing: By using DL, DH or DN commands
To send a packet to an RF module using its 64-bit Address (Transparent Mode)
Set the DH (Destination Address High) and DL (Destination Address Low) parameters of the
source node to match the 64-bit Address (SH (Serial Number High) and SL (Serial Number
Low) parameters) of the destination node.
NI-String Addressing:
The NI string can alternatively be used to address a remote module.
To send a packet to an RF module using its NI-string (Transparent Mode)
Issue the DN (Destination Node) command using the NI (Node Identifier)-string of the destination
node as the parameter.
When the DN command is issued, a broadcast transmission is sent across the network to discover
the module that has a matching NI (Node Identifier) parameter. If a module is discovered with a
matching NI-string, the DH and DL parameters will be configured to address the destination node
and the command will return both the 64-bit Address and the 16-bit Network Address of the
discovered node. Data can be transmitted after the DN (Destination Node) command finishes.
Coordinator Addressing:
Coordinator can be addressed using its 64-bit address or NI string as described in the “NI-String
Addressing” section. Alternatively, since the ZigBee Coordinator has a Network Address of “0”, it
can be addressed by its 16-bit Network Address.
To send a transmission to a Coordinator using its 16-bit Network Address:
Set the Destination Addresses of the transmitting module as shown below:
DL (Destination Low Address) = 0
DH (Destination High Address) = 0
Network Mapping:
Network mapping has provisions to identify all devices on a PAN.There are currently two ways to
do this either through the Node Discover (ND) Command or the API Child Joined Indicator. Both
are explained below.
- Node Discover (ND) Command: Issuing the ND command on a device sends a broadcast node discovery command throughout the
PAN. All devices that receive the command will send a response that includes the device’s 64-bit
and 16-bit addresses, along with the NI-string and other information.
sequences in blue are information sent to the RF module as seen from an X-CTU Terminal screen. Sequences in red are representative of the RF module''''s responses as shown from X-CTU.
P2P
- for 802.15.4 modules exchange addresses of xbee modules with each other
- for zb 25 modules set coordinator DH and DL addresses to end device and set DH and DH addresses for end device = 0 (coordinator has 0 DH and DL)
“Function Set” is the firmware inside XBee. It is responsible for different topologies and configurations.
Source address are fixed to specific modules and destination address are variables
PAN ID same pan id
Loop Back Test Module B Rx and Tx connected with a jumper
Coordinator Range Check Commands:
- Enter command mode "+++" => OK (response in about 2s)
- Report back all nodes "ATND"
- Report specific node "ATDNLOGGER" (LOGGER is end device Node Identifier (NI)), after DN XBee exits AT command mode automatically
Considerations
Use latest firmware
Write configuration to frimware ATWR
Restore factory defaults ATRE before Re-configure
Decoupling capacitor when using voltage regulator 10uF on input and 1uF on output
Micro-controller: do not send continuously delay (10ms)
Remove Rx and Tx connection when uploading code
Links
Loop Back Test: (Pear 2 Pear) http://creativeelectron.net/blog/2009/09/xbee-making-your-first-application-2/
Common Mistakes: http://www.faludi.com/projects/common-xbee-mistakes/
Range Testing: http://www.digi.com/support/kbase/kbaseresultdetl?id=2194
UART Interface
Transparent Mode: Xbee device acts as serial line replacement
What goes in comes out
Host's serial port logic levels are required to be compatible with the Xbee's 2.8-3.4V logic levels. Or logic level conversion is required.
Data presented to Xbee module through its DIN pin must be in the asynchronous serial format
- Start Bit, 8 Data Bits and a stop bit.
Xbee module produces a received data asynchronous serial data stream for the host on its DOUT pin.
Essential Connections for working: DIN, DOUT, Power and Ground.
Faster Data Then Xbee can Process and Transmit it:
CTS (Clear To Send) function to throttle the dat being presented to the XBee module's DIN pin.
Hardware flow control is implemented using XBee's CTS pin
- DI buffer 17 bytes from being los CTS = 1 (logically high) => signal host cease sending data
- Receiving controller pulled enough data from the DI buffer to clear 34 bytes => CTS = 0 (indicate to transmitting node that DI buffer can accept more data)
RTS:
In coming RF data is placed in the DO buffer before being puseed out of the XBee's DO pin.
Hardware flow control of DO buffer is handled by the RTS pin. (data not flow from DO Buffer when RTS = 1)
Programmer can send characters as they are entered to DIN or can buffer in DIN Buffer
Transparent Mode: Data is automatically buffered in DI buffer unless the Packetization Timeout (RO) is set to 0 => Data immediately packetized if RO = 0.
- No serial characters are received within the RO time-out period.
- Max characters that will fit into an RF packet (100) is bufferred.
- A common mode sequence of (GT + CC + GT) is received
Sleep
Please log in to post comments.