Custom Hardware

This section will explain how to adapt a Proprietary RF application from the SimpleLink Low Power F3 SDK to run on custom hardware. In general, the steps required to migrate a Proprietary RF application from a development kit to a custom board are minimal and involve changing the pin configuration as well as selecting the correct RF configuration. These steps, including a bring up guide, are detailed in the subsections below.

Designing a Custom Board

Design guidelines for CC13x2 and CC26x2 boards can be found in the CC13xx/CC26xx Hardware Configuration and PCB Design Considerations app note. This app note includes RF front-end, schematic, PCB, and antenna design considerations. The report also covers crystal oscillator tuning, optimum load impedance as well as a brief explanation of the different power supply configurations.

Note

A similar app note will be produced for the CC23xx devices. In the meantime, we recommend leveraging the reference designs available in the MSR folder.

Creating a Custom Board File

Board files are used by TI drivers to store device specific settings and I/O mapping. The board file abstraction allows one TI-drivers implementation to support many hardware implementations by just setting up new board files. Examples utilize SysConfig to generate these board files. The generated structures are placed in the ti_drivers_config.c and ti_drivers_config.h files. The SysConfig user interface can be utilized to determine pins and resources used. Information on pins and resources used is also present in both of these generated files. It is recommended to use SysConfig to generate the board files for custom hardware as described here.

Configuring Device Parameters for Custom Hardware

  1. Set parameters, such as the sleep clock accuracy of the 32.768-kHz crystal.

  2. Define the CCFG parameters in Device Configuration in SysConfig.

Note

For a description of CCFG configuration parameters, see the CC23xx SimpleLink Wireless MCU Technical Reference Manual.

HFXT Amplitude Compensation

High Frequency Crystal (HFXT) Amplitude Compensation feature adjusts the power amplitude to ensure the high frequency crystal receives sufficient power. The standard HFXT Amplitude Compensation is always enabled - the CC23xx power driver takes care of this.

  • HFXT Amplitude Compensation: At boot within Power_init(), HFXT amplitude is configured to the highest possible value. After this, HFXT amplitude is adjusted to the optimal value each time the device enters standby. It will take up to five iterations after boot until the optimal amplitude is found. This process ensures that the amplitude remains in an optimal range if operating conditions change. This feature will always be enabled, unless Initial HFXT Amplitude Compensation is enabled.

  • Initial HFXT Amplitude Compensation: If the application rarely enters standby, initial HFXT Amplitude Compensation can be enabled when the application requires the optimal amplitude to be found at or after boot. HFXT will take longer to be ready after boot, but when ready the amplitude is already in the optimal range. This process is done asynchronously and is enabled via SysConfig → TI Devices → Device Configuration → Initial HFXT Amplitude Compensation.

    Note

    Enabling initial HFXT amplitude compensation will result in more flash usage and a longer time from boot to first RF operation.

Initial Board Bring Up

When powering up a custom board with the CC23xx for the first time, it is recommended to follow the Board Bring-Up section on CC13xx/CC26xx Hardware Configuration and PCB Design Considerations. After confirming that the board is being powered correctly by the battery or power supply and can be identified by the SWD tool, programming the device with a minimal SW application to verify stability is also suggested.

Using the RGE QFN24 package variant

The CC23xx is also available with a 4-mm x 4-mm RGE QFN24 (12 GPIOs) package variant. See the CC23xx Datasheet for all the package options and IO descriptions.

In order to build SimpleLink Low Power F3 SDK project using the RGE package, a few settings must be made in SysConfig.

  • First open the SysConfig file, click the icon on the top right hand corner Show Board View

  • Click the button SWITCH

  • Select NONE in the Board | New Value field

  • Select the CC2340R5RGE device in the Device field. It automatically updates the package to RGE.

  • Finally click CONFIRM

../_images/SysConfig_RGE_Package_Switch_CC23xx.png

Figure 33. Switch to RGE Package

After clicking CONFIRM, the pins of the SysConfig file may change. If error messages appear, check that the pins changed in SysConfig are consistent with the implemented hardware design.

../_images/SysConfig_RGE_Package_Switch_CC23xx_Error.png

Figure 34. Check the new configuration generated by SysConfig

For each error, review the suggested configuration value, and accept it or modify it.

Tuning HFXT capacitors

One of the features offered by SmartRF Studio 8 is the ability to tune the HFXT capacitors. Generally the RF link could be affected by variations in hardware, this is normally difficult to fix; however with HFXT the RF link can be adjusted by changing the two capacitor values in SmartRF Studio 8.

Tip

TI recommends tuning the HFXT capacitors values for the design. The RF performances improvements obtained by tuning the HFXT capacitors values for each unit on the production line generally do not justify the complexity and added costs.

  1. Download the latest SmartRF 8 Studio

  2. Open SmartRF Studio 8 and open the target device

../_images/smartrf_studio_8_start.png

3. Select the RF settings used by your design. Once SmartRF Studio 8 is open you can view and select various PHYs, to edit a PHY you will need to create a new PHY by clicking on the box next to the PHY name.

../_images/smartrf_studio_8_landing.png

4. You can edit various settings on the PHY properties page such as the custom name, frequency, sync word, and tx power.

../_images/smartrf_studio_8_edit.png

  1. To tune HFXT cap-array tuning change disable to enable and then edit values as needed.

../_images/smartrf_studio_8_edit_hfxt.png

6. To implement the HFXT capacitors values found in the embedded code, open the project in your favorite IDE open the SysConfig file -> Device Configuration and click on “Override HFXT Cap Array Trims” and input the two values found.

../_images/ccs_hfxt_edit_values.png