Constants and functions related to the Comm module. More...
|Comm module functions|
Functions for accessing and modifying Comm module features.
|Comm module constants|
Constants that are part of the NXT firmware's Comm module.
Constants and functions related to the Comm module.
The NXT comm module encompasses support for all forms of Bluetooth, USB, and HiSpeed communication.
You can use the Bluetooth communication methods to send information to other devices connected to the NXT brick. The NXT firmware also implements a message queuing or mailbox system which you can access using these methods.
Communication via Bluetooth uses a master/slave connection system. One device must be designated as the master device before you run a program using Bluetooth. If the NXT is the master device then you can configure up to three slave devices using connection 1, 2, and 3 on the NXT brick. If your NXT is a slave device then connection 0 on the brick must be reserved for the master device.
Programs running on the master NXT brick can send packets of data to any connected slave devices using the BluetoothWrite method. Slave devices write response packets to the message queuing system where they wait for the master device to poll for the response.
Using the direct command protocol, a master device can send messages to slave NXT bricks in the form of text strings addressed to a particular mailbox. Each mailbox on the slave NXT brick is a circular message queue holding up to five messages. Each message can be up to 58 bytes long.
To send messages from a master NXT brick to a slave brick, use BluetoothWrite on the master brick to send a MessageWrite direct command packet to the slave. Then, you can use ReceiveMessage on the slave brick to read the message. The slave NXT brick must be running a program when an incoming message packet is received. Otherwise, the slave NXT brick ignores the message and the message is dropped.