Example Summary

This example is the same as the “portable” example but instead of using POSIX APIs, it uses the native RTOS APIs. This example is still portable across devices (because of TI Drivers). This project requires less code/data space since there is no POSIX layer.

Peripherals & Pin Assignments

When this project is built, the SysConfig tool will generate the TI-Driver configurations into the ti_drivers_config.c and ti_drivers_config.h files. Information on pins and resources used is present in both generated files. Additionally, the System Configuration file (*.syscfg) present in the project may be opened with SysConfig’s graphical user interface to determine pins and resources used.

• CONFIG_GPIO_LED_0 - Indicates that temperature has exceeded the alert threshold.
• CONFIG_GPIO_BUTTON_1 - Used to restart the UART console.
• CONFIG_UART2_0 - Used for a simple console.
• CONFIG_I2C_TMP - Used to read temperature.

If using the Building Automation Sensors BoosterPack, BP-BASSENSORSMKII, CONFIG_GPIO_TMP_EN is used to power on the BoosterPack’s temperature sensor.

BoosterPacks, Board Resources & Jumper Settings

• For boards without an on-board TMP sensor, this example requires a BP-BASSENSORSMKII BoosterPack. It has the TMP117 sensor along with several I2C sensors.

For board specific jumper settings, resources and BoosterPack modifications, refer to the Board.html file.

If you’re using an IDE such as Code Composer Studio (CCS) or IAR, please refer to Board.html in your project directory for resources used and board-specific jumper settings.

The Board.html can also be found in your SDK installation:

<SDK_INSTALL_DIR>/source/ti/boards/<BOARD>

Example Usage

• Open a serial session (e.g. PuTTY, etc.) to the appropriate COM port.
  • The COM port can be determined via Device Manager in Windows or via ls /dev/tty* in Linux.

The connection should have the following settings:

    Baud-rate:  115200
    Data bits:       8
    Stop bits:       1
    Parity:       None
    Flow Control: None

• Run the example.

• The target displays a simple console on the serial session.

    Valid Commands
    --------------
    h: help
    q: quit and shutdown UART
    c: clear the screen
    t: display current temperature

• The silicon die temperature is displayed. You’ll need to change the temperature of the actual TMP sensor to see a change.

• If you quit the console, the device will go into a lower power mode. To start the console back up, hit the restart button.
  • Note: depending on the TMP sensor you are using, the initial readings of the TMP sensor might be invalid when coming out of the low power mode. Please refer to the TMP sensor data sheet for more details.

Application Design Details

• This example shows how to initialize the UART driver in blocking read and write mode.

• A thread, consoleThread, is a simple console. When the UART is closed the device can go into a lower power mode.

• A thread, temperatureThread, reads the temperature via I2C. The thread reads the sensor every second. The timing is controlled by a timer and semaphore. This approach was used to eliminate time drift (which would have occurred with simply using sleep(1)).

• The disabling of interrupts/tasking (depending on the kernel you are using) is used to protect the reading/writing of the temperature variables. The reading/writing of these two variables must be done atomically. For example without critical region management, the temperature thread (which is higher priority) could interrupt the reading of the variables by the console thread. This could result with the console thread printing a Celsius value that did not match up with the Fahrenheit value.

FreeRTOS:

• Please view the FreeRTOSConfig.h header file for example configuration information.

SimpleLink Sensor and Actuator Plugin:

• This example uses a TMP sensor. It interfaces via the I2C Driver. For a richer API set for the TMP sensors, please refer to the SimpleLink Sensor and Actuator Plugin.