rfEasyLink_rx Example

Example Summary

Example includes the EasyLink API and uses it to configure the RF driver to RX packets. This project should be run in conjunction with the rfEasyLinkTx project.

For more information on the EasyLink API and usage refer to https://processors.wiki.ti.com/index.php/SimpleLink-EasyLink

Peripherals Exercised

• Board_PIN_LED1 - Indicates an abort which is expected to happen 300 ms after RX has been scheduled
• Board_PIN_LED2 - Indicates that a packet has been received Board_PIN_LED1 & Board_PIN_LED2 indicate an error
• Board_GPTIMER0A - Used to timeout the receive operation if it runs over 300ms in the no-RTOS asynchronous implementation

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>.

Example Usage

Run the example. Board_PIN_LED2 will toggle indicating a packet has been received. Board_PIN_LED1 will toggle indicating an abort, which is expected to happen if a packet is not received within 300 ms of the RX being scheduled. Board_PIN_LED1 and Board_PIN_LED2 indicates an error (not expected to happen under normal conditions, but may occur if there is some interference).

After running this application you should start the rfEasyLinkTx on a second board to transmit packets. Until the rfEasyLinkTx has been started the receiver will be continuously RX.

Application Design Details

This example shows how to use the EasyLink API to access the RF drive, set the frequency and receive packets. The board will blink LED2 when a packet has been received. When a second board is running rfEasyLinkTx example then the expected behavior is that Board_PIN_LED2 will blink every 100 ms 10 times, the TX will then wait for 300 ms before transmitting the next packets and if RFEASYLINKRX_ASYNC is defined (as it is by default) then this will cause the rfEasyLinkRx example to timeout and exercise the EasyLink_abort API. When an RX has been aborted Board_PIN_LED1 should toggle. The rfEasyLinkTx board will then transmit another burst of packets and Board_PIN_LED2 should blink another 10 times and the cycle should repeat.

If RFEASYLINKRX_ADDR_FILTER is defined (as it is by default) then the RX address filter will be enabled for address 0xaa. This will cause the rfEasyLinkRx to only accept packets with a destination address of 0xaa, which the rfEasyLinkTx example transmits. When using the rfEasyLinkTx example there will be no difference in behavior when defining/undefining RFEASYLINKRX_ADDR_FILTER as the rfEasyLinkTx example will use a destination address of 0xaa. However, if transmitting from another source like SmartRF Studio and not using an address of 0xaa, then defining RFEASYLINKRX_ADDR_FILTER will result in packets not being received.

A single task, “rfEasyLinkRxFnx”, configures the RF driver through the EasyLink API and receives messages.

EasyLink API

Overview

The EasyLink API should be used in application code. The EasyLink API is intended to abstract the RF Driver in order to give a simple API for customers to use as is or extend to suit their application[Use Cases] (@ref USE_CASES).

General Behavior

Before using the EasyLink API:

• The EasyLink Layer is initialized by calling EasyLink_init(). This initializes and opens the RF driver and configures a modulation scheme passed to EasyLink_init.
• The RX and TX can operate independently of each other.

The following is true for receive operation:

• RX is enabled by calling EasyLink_receive() or EasyLink_receiveAsync()
• Entering RX can be immediate or scheduled
• EasyLink_receive() is blocking and EasyLink_receiveAsync() is non-blocking
• The EasyLink API does not queue messages so calling another API function while in EasyLink_receiveAsync() will return EasyLink_Status_Busy_Error
• An Async operation can be cancelled with EasyLink_abort()

The following apply for transmit operation:

• TX is enabled by calling EasyLink_transmit(), EasyLink_transmitAsync() or EasyLink_transmitCCAAsync()
• TX can be immediate or scheduled
• EasyLink_transmit() is blocking and EasyLink_transmitAsync(), EasyLink_transmitCCAAsync() are non-blocking
• EasyLink_transmit() for a scheduled command, or if TX cannot start
• The EasyLink API does not queue messages so calling another API function while in either EasyLink_transmitAsync() or EasyLink_transmitCCAAsync() will return EasyLink_Status_Busy_Error
• An Async operation can be cancelled with EasyLink_abort()

Error Handling

The EasyLink API will return EasyLink_Status containing success or error code. The EasyLink_Status codes are:

• EasyLink_Status_Success
• EasyLink_Status_Config_Error
• EasyLink_Status_Param_Error
• EasyLink_Status_Mem_Error
• EasyLink_Status_Cmd_Error
• EasyLink_Status_Tx_Error
• EasyLink_Status_Rx_Error
• EasyLink_Status_Rx_Timeout
• EasyLink_Status_Busy_Error
• EasyLink_Status_Aborted

Power Management

The power management framework will try to put the device into the most power efficient mode whenever possible. Please see the technical reference manual for further details on each power mode.

The EasyLink Layer uses the power management offered by the RF driver Refer to the RF Driver documentation for more details.

No-RTOS Implementation

The No-RTOS implementation uses a general purpose timer to timeout the receive operation, for the asynchronous case, if it exceeds 300ms.

Supported Functions

| Generic API function          | Description                                        |
|-------------------------------|----------------------------------------------------|
| EasyLink_init()               | Init's and opens the RF driver and configures the  |
|                               | specified modulation                               |
| EasyLink_transmit()           | Blocking Transmit                                  |
| EasyLink_transmitAsync()      | Non-blocking Transmit                              |
| EasyLink_transmitCCAAsync()   | Non-blocking Transmit with Clear Channel Assessment|                                               
| EasyLink_receive()            | Blocking Receive                                   |
| EasyLink_receiveAsync()       | Non-blocking Receive                               |
| EasyLink_abort()              | Aborts a non-blocking call                         |
| EasyLink_EnableRxAddrFilter() | Enables/Disables RX filtering on the Addr          |
| EasyLink_GetIeeeAddr()        | Gets the IEEE Address                              |
| EasyLink_SetFreq()            | Sets the frequency                                 |
| EasyLink_GetFreq()            | Gets the frequency                                 |
| EasyLink_SetRfPwr()           | Sets the TX Power                                  |
| EasyLink_GetRfPwr()           | Gets the TX Power                                  |

Frame Structure

The EasyLink implements a basic header for transmitting and receiving data. This header supports addressing for a star or point-to-point network with acknowledgements.

Packet structure:

 _________________________________________________________
|           |                   |                         |
| 1B Length | 1-64b Dst Address |         Payload         |
|___________|___________________|_________________________|

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.