rfWsnNode Example

Example Summary

The WSN Node example illustrates how to create a Wireless Sensor Network Node device which sends packets to a concentrator. This example is meant to be used together with the WSN Concentrator example to form a one- to-many network where the nodes send messages to the concentrator.

This examples showcases the use of several Tasks, Semaphores and Events to get sensor updates and send packets with acknowledgment from the concentrator. For the radio layer, this example uses the EasyLink API which provides an easy-to-use API for the most frequently used radio operations.

Peripherals Exercised

• Board_PIN_LED0 - Toggled when a packet is sent
• Board_ADCCHANNEL_A0 - Used to measure the Analog Light Sensor by the SCE task
• Board_PIN_BUTTON0 - Selects fast report or slow report mode. In slow report mode the sensor data is sent every 5s or as fast as every 1s if there is a significant change in the ADC reading. In fast reporting mode the sensor data is sent every 1s regardless of the change in ADC value. The default is slow reporting mode.

System Confirguration Tool (SysConfig) Setup

Driver Configuration

• RF - RF Driver Configuration
  • Hardware Used - RF Antenna Switch
• Power - Power Manager Configuration
  • Default options used
• GPIO - GPIO Configuration
  • Hardware Used - LaunchPad LED Red
• GPIO - GPIO Configuration
  • Hardware Used - LaunchPad Button BTN-1 (left)
• Display - Display Configuration
  • Hardware Used - XDS110 UART
• Display - Display Configuration
  • Hardware Used - Sharp LCD Display (BOOSTXL-SHARP128)
• SPI - Serial Peripheral Interface Configuration
  • Hardware Used - MX25R8035F 1MB SPI Flash

EasyLink Stack Configuration

• RF Settings - PHY Configuration
  • Default PHY - Custom
  • Additional Supported PHYs - Custom
• Advanced Settings - Advanced Settings Configuration
  • Asynchronous Rx Timeout (ms) - 160

Resources & Jumper Settings

If you’re using an IDE (such as CCS or IAR), please refer to Board.html in your project directory for resources used and board-specific jumper settings. Otherwise, you can find Board.html in the directory <SDK_INSTALL_DIR>/source/ti/boards/<BOARD>.

Board Specific Settings

1. The WSN examples use the custom physical mode by default, which sets the center frequency to:
   • 433.92 MHz for the CC1350-LAUNCHXL-433
   • 433.92/490 MHz for the CC1352P-4-LAUNCHXL
   • 2440 MHz on the CC2640R2-LAUNXHL
   • 868.0 MHz for other launchpads In order to change frequency, modify the smartrf_settings.c file. This can be done using the code export feature in Smart RF Studio, or directly in the file
2. On the CC1352P1 the high PA is enabled (high output power) for all Sub-1 GHz modes by default.
3. On the CC1352P-2 the high PA operation for Sub-1 GHz modes is not supported
4. On the CC1352P-4 the high PA is enabled (high output power) for all Sub-1 GHz modes by default.
   • The center frequency for 2-GFSK is set to 490 MHz
   • CAUTION: The center frequency for SimpleLink long range (SLR) is set to 433.92 MHz, but the high output power violates the maximum power output requirement for this band
5. The CC2640R2 is setup to run all proprietary physical modes at a center frequency of 2440 MHz, at a data rate of 250 Kbps

Example Usage

• Run the example. On another board run the WSN Concentrator example. This node should show up on the serial console and LCD of the Concentrator. As the LED toggles the Node ADC Reading will update on the display.

Node ID: 0xa9
Node ADC Reading: 0010

Application Design Details

• This examples consists of two tasks, one application task and one radio protocol task. It also consists of an Sensor Controller Engine, SCE, Task which samples the ADC.

• On initialization the CM3 application sets the minimum report interval and the minimum change value which is used by the SCE task to wake up the CM3. The ADC task on the SCE checks the ADC value once per second. If the ADC value has changed by the minimum change amount since the last time it notified the CM3, it wakes it up again. If the change is less than the masked value, then it does not wake up the CM3 unless the minimum report interval time has expired.

• The NodeTask waits to be woken up by the SCE. When it wakes up it toggles Board_PIN_LED1 and sends the new ADC value to the NodeRadioTask.

• The NodeRadioTask handles the radio protocol. This sets up the EasyLink API and uses it to send new ADC values to the concentrator. After each sent packet it waits for an ACK packet back. If it does not get one, then it retries three times. If it did not receive an ACK by then, then it gives up.

RadioProtocol.h can also be used to change the PHY settings to be either the default IEEE 802.15.4g 50kbit, Long Range Mode or custom settings. In the case of custom settings, the smartrf_settings.c file is used. This can be changed either by exporting from Smart RF Studio or directly in the file.

Note for IAR users: When using the CC1310DK, the TI XDS110v3 USB Emulator must be selected. For the CC1310_LAUNCHXL, select TI XDS110 Emulator. In both cases, select the cJTAG interface.

References

• For more information on the EasyLink API and usage refer to SimpleLink-EasyLink.

EasyLink Stack Configuration using the System Configuration Tool (SysConfig)

Overview

The purpose of SysConfig is to provide an easy to use interface for configuring drivers, RF stacks, and more. Many parameters of the EasyLink stack can be configured using SysConfig including address filtering, clear channel assessment parameters, RF settings, and advanced settings.

Basic Configuration

The basic EasyLink stack configuration includes address filtering, address size, and max data length. When these paramters are configured via SysConfig, they will take affect when the EasyLink_init() API is called.

Clear Channel Assessment (CCA) Configuration

The CCA configuration parameters are used when checking if a channel is clear of traffic before transmitting. The combination of RSSI threshold and channel idle time define what is considered a “clear” channel. The max and min backoff window, backoff time units, and random number generation function define the behavior when the channel is sniffed and found to be busy. The CCA configuration parameters take affect when using the EasyLink_transmitCcaAsync() API.

Advanced Configuration

The advanced configuration parameters require in-depth knowledge of the EasyLink APIs. For more information on these configuration parameters please see the EasyLink_CtrlOption enumeration for use with the EasyLink_setStrl() API. When the advanced configuration parameters are configured via SysConfig, they take affect when the EasyLink_init() API is called with the exception of the Asynchronous Rx Timeout (ms) and the Test Mode Whitening paramters. These require the use of the EasyLink_receiveAsync() and EasyLink_setCtrl() APIs respectively.

RF Configuration

The RF configuration of the EasyLink stack includes setup of both the RF driver and any PHYs the application needs to support. The RF Driver provides access to the radio core and offers a high-level interface for command execution that is utilized by the EasyLink APIs. Configuration of the PHY settings includes selecting the default PHY that will be used when the EasyLink_init() API is called as well as any additional supported PHYs. As each PHY is added to the configuraiton a Radio Configuration module will provide the ability to customize settings such as frequency, power, etc. All the RF configuration parameters take affect when calling the EasyLink_init() API.

Responsibilities of the Application

Several EasyLink stack parameters configured in SysConfig require the application to use specific EasyLink APIs to take affect. The following table shows which parameters that require the use of these APIs in the application.

| Configuration Parameter(s)          | EasyLink API needed to take Affect                 |
|-------------------------------------|----------------------------------------------------|
| All parameters                      | EasyLink_init()                                    |
| Clear Channel Assessment Parameters | EasyLink_transmitCcaAsync()                        |
| Asynchronous Rx Timeout (ms)        | EasyLink_receiveAsync()                            |
| Test Mode Whitening                 | EasyLink_setCtrl()                                 |

Provided SysConfig Files

The .syscfg file provided with an EasyLink stack example project has been configured and tested with that project. Changes to the .syscfg file can and will alter the behavior of the example. Some stack parameters configured in SysConfig will require the use of specific EasyLink APIs to take affect. Please refer to the Responsibilities of the Application section of this document for further information on which configuration parameters require the use of specifc APIs.