In this page we present a customization, called TerraGrp, that uses the basic library of components, which includes the high-level abstractions for group management.
The Terra customization, apart local sensors readings, provides an way to define by parameters multiple group of nodes. The "send" and "receive" events applies to a predefined group of nodes. Also includes some value aggregations for group of nodes. Table 4 presents the current TerraGrp events interface and Table 5 presents the functions interface.
The local operations comprises operations to read sensors and residual energy battery, define led's configuration and access input and output devices of the microcontroller. Terra encapsulates all these operations in a component called Local Operations providing them as output events. Timers, on the other hand, are handled directly by the Céu-T language with the await time command.
The SEND() command is a basic send command that reach all nodes in a group definition. If the field target is set to BROADCAST value, all nodes in the group will receive the message. On the other hand, if this field is set to a specific node identifier, only this node will receive the message (if the node is in the group definition). A SEND_DONE() event indicates that the send request was processed by the radio. The RECEIVE event returns a received message. Additionally, TerraGrp implements the SEND_BS() command that router a message to the root node.
The user must define the radio message data structure using pktype command and then create a message variable.
| Description | Output event (emit) | Input event (await) | |||
|---|---|---|---|---|---|
| Event identifier | Argument type | Returned type | Event identifier | Argument type | |
| Set all three leds - The less three significative bits of the argument will set the leds. | LEDS | ubyte | |||
| Set LED0 - Argument can be ON, OFF, or TOGGLE. | LED0 | ubyte | |||
| Set LED1 - Argument can be ON, OFF, or TOGGLE. | LED1 | ubyte | |||
| Set LED2 - Argument can be ON, OFF, or TOGGLE. | LED2 | ubyte | |||
| Temperature Sensor - Requests and receives the sensor value. The received value is a 10bit reading from A/D converter. This is not the physical unit. | REQ_TEMP | void | ushort | TEMP | void |
| Luminosity Sensor - Similar to the others sensors. | REQ_PHOTO | void | ushort | PHOTO | void |
| Voltage Sensor - Similar to the others sensors. | REQ_VOLTS | void | ushort | VOLTS | void |
| Custom event - This is a internal loopback event that allows to pass a integer value. The await command may define or not which value to wait. | REQ_CUSTOM_A | ubyte | ubyte | CUSTOM_A | void or ubyte |
| Send radio message to the BaseStation node. The argument in the await event may be used to wait only a specific message type identifier. | SEND_BS | msgBS_t | ubyte | SENDBS_DONE | void or ubyte |
| Send radio message to the group nodes. The argument in the await event may be used to wait only a specific message type identifier. | SEND_GR | msgGR_t | ubyte | SENDGR_DONE | void or ubyte |
| Execute an aggregation value for a group nodes. The argument in the await event may be used to wait only a specific message type identifier./td> | AGGREG | aggreg_t | aggDone_t | AGGREG_DONE | void or ubyte |
| Receive radio message from a group node- returns a radioMsg variable received by the radio. The argument in the await event may be used to wait only a specific message type identifier. | msgGR_t | REC_GR | void or ubyte | ||
| Error trap - Indicates a internal errors like E_DIVZERO and E_IDXOVF, respectively division by zero and array index overflow. | ubyte | ERROR | void or ubyte | ||
| Description | Returned type | Function name | arguments |
|---|---|---|---|
| Return the node identifier | ushort | getNodeId | void |
| Return a 16bit random number | ushort | random | void |
| Return the internal timer counter | ulong | getTime | void |
| Initialize a Group data structure. Always returns SUCCESS. | ubyte | groupInit | group_t grVar, ubyte ID1, ubyte ID2, ubyte nHops, ubyte status, ubyte elFlag, ushort leader |
| Initialize an Aggregation data structure. Always returns SUCCESS. | ubyte | aggregInit | aggreg_t agVar, group_t grVar, ubyte sensorId, ubyte agOper, ubyte agComp, ulong refVal |
| Return the current parent node in the CTP routing tree | ushort | getParent | void |
| Set the radio transmit power level. Always returns SUCCESS. | ubyte | setRFPower | ubyte level |
| Constant | Value | Description |
|---|---|---|
| SUCCESS | 0 | Indicates a Success operation |
| TRUE | 1 | A true value |
| FALSE | 0 | A false value |
| ON | 1 | Set LED ON |
| OFF | 0 | Set LED OFF |
| TOGGLE | 2 | Set LED with oposite value |
| BROADCAST | 0xffff | Define a broadcast message |
| E_DIVZERO | 10 | Error event - Division by zero |
| E_IDXOVF | 11 | Error event - Array index overflow |
| E_STKOVF | 20 | Error event - Stack overflow -- fatal |
| opLT | 1 | LT - "<" operation |
| opLTE | 2 | LTE - "<=" operation |
| opGT | 3 | GT - ">" operation |
| opGTE | 4 | GTE - "<=" operation |
| opEQ | 5 | EQ - "==" operation |
| opNEQ | 6 | NEQ - "!=" operation |
| fAVG | 0 | Aggreg Functions - Average |
| fSUM | 1 | Aggreg Functions - Summation |
| fAVG | 0 | Aggreg Functions - Average |
| fMAX | 2 | Aggreg Functions - Maximum value |
| fMIN | 3 | Aggreg Functions - Minimum value |
| SID_TEMP | 1 | Sensor IDs - Temperature |
| SID_PHOTO | 2 | Sensor IDs - Luminosity |
| SID_LEDS | 3 | Sensor IDs - Leds |
| SID_VOLT | 1 | Sensor IDs - Voltage |
| eACTIVE | 1 | Group Election Status - Node participate activitely. |
| ePASSIVE | 3 | Group Election Status - Node participate, but not vote to be a leader. |
| eOFF | 3 | Group Election Status - Node is disabled on the election procedure |