# Available Flash Variants with RSL15

The available RSL15 flash variants are:

- RSL15 (RSL15-512)

  - This variant provides 512 KB of flash memory, divided into a code flash array of 352 KB and a data flash array of 160 KB.

  - This is the default RSL15 variant, and all sample applications and device configuration is configured to work with this variant by default.

  - When debugging code running on this variant, specify RSL15 as the device name on the debugger tab of the debug configuration.

- RSL15-284:

  - This variant provides 284 KB of flash memory, divided into a code flash array of 264 KB and a data flash array of 20 KB.

  - This variant uses different build configurations that are appropriate for the reduced memory layout. To configure the tools for use with this variant, see Available Flash Variants with RSL15.

  - When debugging code running on this variant, specify RSL15-284 as the device name on the debugger tab of the debug configuration.

NOTE: Debugging an application built and configured for RSL15-284 on an RSL15-512 device functions correctly. Debugging an application built and configured for an RSL15-512 on a RSL15-284 device fails if any memory accesses are attempted to the memories that are not instantiated on RSL15-284.

IMPORTANT: As the RSL15-284 variant has a reduced memory footprint, users must take extra care to ensure that their use case fits into memory. Use of this variant limits the size of user applications and combinations of key firmware components, including the Bluetooth stack, Firmware over the air (FOTA) update functionality, and security operations using the Arm CryptoCell-312 that can be supported.