The CC3200 SDK provides a peripheral driver library and hardware register access header files for the Texas Instruments SimpleLink CC3200 SoC. The current version supported in Zephyr is CC3200 SDK V1.2.0, downloaded from: http://www.ti.com/tool/cc3200sdk Files in driverlib/ and inc/ are copied from an SDK installation (without modification). After setting CONFIG_HAS_CC3200SDK=y in Kconfig, there are two methods for using the peripheral driver library: 1) (Default) Use the driverlib functions in ROM instead of RAM. TI provides the driver library functions burned into ROM at the factory, or updated via a service pack patch, thus saving application code space. For the zephyr shell sample, for example, this resulted in a savings of about 2Kb in code space. Setting CONFIG_CC3200SDK_ROM_DRIVERLIB enables all driverlib APIs prefixed by "MAP_" to vector to those functions already existing in ROM. See: Section 6.2.2 "Linking User Application with ROM APIs", CC3200 Programmer's Guide, www.ti.com/lit/pdf/swru369 2) Use the driver library functions built from the CC3200SDK files in Zephyr. Setting CONFIG_CC3200SDK_BUILTIN allows building those files within the Zephyr ext/hal/ti/ subdirectory. Though this will take more code space than using the ROM driverlib functions, this may be useful for debugging purposes. Applications can use the two configurations simultaneously: For example, calling APIs without the "MAP_" prefix would call into Zephyr-built driver lib functions in RAM, while calling APIs with the "MAP_" prefix would call into the ROM.