TI SimpleLink™ Bluetooth® LE CC2640R2F LaunchPad - Review

Table of contents

RoadTest: TI SimpleLink™ Bluetooth® LE CC2640R2F LaunchPad

Author: shwetankv007

Creation date:

Evaluation Type: Independent Products

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: texas cc2650 launchpad with its own pros and cons, Intel tiny tile module, the Nordic Blend2 based on nRF52832.

What were the biggest problems encountered?: The initial documentations from a beginner point of view are bit complex, for both the hardware and software support.

Detailed Review:

INTRODUCTION

The Texas Instruments launchpad houses the cc2640r2 simplelink BLE MCU which is based on the powerful ARM Cortex M3 with a clock speed of upto 48MHz. The controller has a 16 bit architecture with 128KB of programming memory and a 28KB SRAM (20KB low leakage + 8KB cache ).

The controller also supports OTA(over the air)upgrade as suggested by the technical datasheet of the wireless controller, however I have not tested the same.

The wireless part has a 2.4GHz Transceiver compatible with Bluetooth 4.2 and 5. The datasheet suggests sensitivity of upto -97dBm which has been tested in the further review.

The Launchpad in all is a complete breakout board  that gives the required number of GPIOs for connecting the peripherals and a reliable BLE communication medium. The current package used in the Launchpad provides about 31 GPIOs for the purpose. The Launchpad is a one stop solution for the IoT applications, security systems and sensor nodes communication hub.

Other specifications:-

  • The Launchpad also houses a debugger circuit using the TM4C1294 controller supporting the XDS110.
  • On board LEDs, there are two onboard LEDs connected to the D106 and D107 pins which are connected via the jumpers that can be removed in order to use it as GPIOs.
  • Two on board general buttons connected to GPIOs 13 and 14.
  • The cc2640 chip is a 1.8-3.8 volt logic and hence the internal DC-DC convertors.

 

 

THE FIRST VIEW

The module however is really cool and arrived in good condition, it has a micro USB port that is generally used for powering up the board and uploading the code to it, the cc2640r2 wireless MCU sits in the lower middle surrounded by the breakout components. There is a master reset switch which reboots the module the code is uploaded via the debugger module, this part however can be removed by removing the jumpers in the middle.

The pack had a USB cable a pinout sheet and the module itself, the package also had the instruction manual with the required RoHS compliant.

the complete pinout diagram of the launchpad is as shown below.

 

ELECTRICAL OVERVIEW AND BOARD INVESTIGATION

The cc2640r2 MCU is strictly a 3.3volt controller however it can be externally powered using the micro USB port and the power header.

The Launchpad uses a very minimal number of external components since the wireless MCU houses a lot of internal peripherals, hence requiring very minimal external components including the external oscillator.

Let us study the hardware schematics to get a clear understanding about the connections and the components.

The wireless MCU is to be connected to power using the decoupling capacitors, the pins 13, 22, 34 and 44 are to be connected to the power. The pins 45 and 48 are however connected to the internal DC-DC convertor output from pin33. As shown in the schematic layout the decoupling capacitors are used to connect the power pins.

Coming to the RF section of schematic the two oscillators are connected i.e. 24MHz that is the processing clock of the Launchpad and a 32.768KHz oscillator for the internal RTC and timer operations. The circuit also shows the onboard antenna along with the matching circuit.

THE GPIO SECTION

As discussed earlier the current package used in the Launchpad gives 31 GPIOs which are connected to the header breakouts, moreover an external flash is also connected along with the header circuit.

   

The debugger circuit is however an extra add-on to the Launchpad and comprises of the TM4C1294 microcontroller centered around ARM cortex M4 controller and few discrete components to drive the circuit including three 4-bit dual supply bus transceiver to support the voltage conversions and maintain the speed of transfers.

This part is however removable by removing the jumpers at the center and connecting the board using external supply.

 

 

SOFTWARE SETUP

The Launchpad can be programmed using the code composer studio or CCS cloud. The earlier is an Eclipse based IDE and provides a wide range of tool set for the operation debugging the code and uploading to the module.

All you need to do is to download the latest code composer studio Download CCS - Texas Instruments Wiki

Follow the basic installation procedure and open the IDE. Now in order to use your Launchpad with the IDE go to the recource explorer and search for the required SDK under the software section.

We can use the examples and take a look at the necessary documentations of the launchpad.

The SDK also has a set of examples to start with go to

Software>simplelink cc2640r2 sdk > examples > Development tools > CC2640R2 Launchpad

And you can find a list of demos, drivers and examples to work with.

Moreover the SDK includes Simplelink Academy that is a detailed description on getting started from basics to experienced developer, the academy tool involves a quick guide to drivers and tools offered by the Launchpad and few videos for the same.

The Launchpad however is already installed with the beginner code and we can directly connect it to our Bluetooth smartphones.

Simplelink starter app is available for Android as well as IOS devices and can be readily used to connect the Launchpad. After the connection is established the app communicates with all the services and gives the respective information.

The app shows RSSI data and button state of the Launchpad, the pulse of both buttons is shown in the app when they are pressed.

 

The nRF Connect APP:-

This app is quite useful as it tells a lot about the bluetooth connection itself and displays many published services. I used the first launchpad code that is already present on the board and connect using the app, we get the published parameters.

The app also took a log of the RSSI values i.e. received signal strength indicator in dbm, I took several RSSI value depending on the distance from the board and it gave a good response, more than what I expected. The Bluetooth range of the device is quite negotiable.

 

I took a graph of changing RSSI values with distance using the nRF app.

The App is quite useful, I also used the app to connect to the project zero and control the onboard LEDs using the write services. The read and write tabs are very handy and can be used to communicate with the required services.

 

 

CONCLUSION

The TI Launchpad with simplelink BLE cc2640r2 is a really reliable module with huge possibilities for many IoT, security system and many other projects. This is in succession to the cc2650 series however both of these are quite different in terms of RF connectivity. The ARM cortex M3 controller with its architecture gives the MCU an edge with other BLE boards such as the tinytile. In my opinion the cc2640r2 is quite different with cc2650 since the later is a multistandard wireless microcontroller module however cc2640r2 focusses on the BLE applications.

The module however is very good in terms of hardware reliability and software support, for a beginner however I would not suggest the same since the IDE is not as simpler as Arduino but the simplelink academy does helps a lot for the basic understanding.

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