Peer-to-peer Application

This sample shows how to organize the simplest peer-to-peer link. A simple buffering strategy is employed to avoid byte-by-byte data transfer.

At least 2 nodes are participating. Up to 8 nodes can be engaged. In order to define the node logical addresses, set DIP switches as shown below. One of the nodes should be configured as coordinator (i.e. its logical address should be set to zero). All of the nodes which are connected over UART to their own USB ports simply exchange over UART with data sent to them by their hosts. The connection parameters should be set in the following way:

Parameter	Value
Data Rate	38400 bps
Data Bits	8
Parity	None
Stop Bits	1
Flow Control	Hardware

The nodes communicate strictly in pairs defined by their logical addresses as follows:

• node 0 with node 1;
• node 2 with node 3;
• node 4 with node 5;
• node 6 with node 7.

Node	DIP switches
	SW4:1	SW4:2	SW4:3
0	OFF	OFF	OFF
1	ON	OFF	OFF
2	OFF	ON	OFF
3	ON	ON	OFF
4	OFF	OFF	ON
5	ON	OFF	ON
6	OFF	ON	ON
7	ON	ON	ON

The network organizes automatically on startup. You may connect two devices to a PC (or to different PCs, thus introducing a rough functional equivalent of an instant messenger), start two instances of HyperTerminal, type some message in one terminal window and observe it appearing in the another.

Pressing SW1 button on a node results in sending a single maximum-length frame filled with 0xDD byte.

LEDs indicate network activity as follows:

• when a node is searching for the network, green LED is blinking;
• green LED is ON when the node joins the network successfully;
• red LED is flashing when the node is sending data;
• yellow LED flashing indicates the node is receiving data.

Configuration parameters

APP_CHANNEL_MASK	Specifies channels to be tried by nodes for network operation
APP_COORD_UID	Coordinator UID; is used as coordinator MAC address
APP_USE_APS_ACK	Indicates whether the APS level ack will be used or not
TIMER_STARTING_NETWORK	LED blinking interval during network start (ms)
TIMER_FW_DELAY	Interval before forwarding of the received packet (ms)

The source codes of Peer-to-peer application are located at [ZDK]\Sample Applications\Peer2peer directory.

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