OpenThread stack memory layout

The following figures present a typical flash and RAM layout for an application that uses the OpenThread stack in single and multiprotocol scenarios.

OpenThread stack flash and RAM layout

OpenThread stack flash and RAM layout for multiprotocol Thread/BLE solution

For details on the values of APP_CODE_BASE and APP_RAM_BASE, see S140 SoftDevice memory resource map and usage.

The following figure shows a typical ROM layout for an application that uses MBR and Secure DFU Bootloader over Serial Link (UART/USB).

OpenThread stack ROM layout (nRF52840 and nRF52833)

Flash and RAM requirements for nRF52840 and nRF52833

The following tables list flash memory and RAM requirements for the applications compiled with different options using the GCC compiler with size optimization. The values change depending on the application and platform.

The values in the tables are provided for the CLI example, which works with all OpenThread calls. For this reason, these values are the best approximation of the memory requirements.

You can adjust the RAM memory requirements, for example to support different number of children, buffers, or registered addresses. The default configuration is defined in the following files:

openthread-core-default-config.h
Use the core default config file with the respective platform configuration file:
- openthread-core-nrf52840-config.h
- openthread-core-nrf52833-config.h

For information about each library variant and features it supports, see the library page.

Flash and RAM requirements for nRF52840

The following table lists values for the nRF52840 platform.

Role	OpenThread library variant	App	Multiprotocol	Flash [KB] (OpenThread stack + app)	Persistent Data [KB]	RAM [KB] (OpenThread stack + app)	Flash [KB] (BLE stack)	RAM [KB] (BLE stack)	Total ROM [KB]	Total RAM [KB]
Router	Master	cli	yes	358	16	80	156	11	530	91
End Device	Master	cli	yes	299	16	72	156	11	471	83
Router	Optimized	cli	yes	337	16	80	156	11	509	91
End Device	Optimized	cli	yes	277	16	71	156	11	449	82
Router	Master	cli	no	344	16	79	0	0	360	79
End Device	Master	cli	no	285	16	70	0	0	301	70
Router	Optimized	cli	no	323	16	78	0	0	339	78
End Device	Optimized	cli	no	263	16	69	0	0	279	69

Flash and RAM requirements for nRF52833

The following table lists values for the nRF52833 platform.

Role	OpenThread library variant	App	Multiprotocol	Flash [KB] (OpenThread stack + app)	Persistent Data [KB]	RAM [KB] (OpenThread stack + app)	Flash [KB] (BLE stack)	RAM [KB] (BLE stack)	Total ROM [KB]	Total RAM [KB]
Router	Master	cli	yes	293	8	71	156	11	457	82
End Device	Master	cli	yes	235	8	63	156	11	399	74
Router	Optimized	cli	yes	273	8	70	156	11	437	81
End Device	Optimized	cli	yes	213	8	62	156	11	377	73
Router	Master	cli	no	280	8	69	0	0	288	69
End Device	Master	cli	no	221	8	61	0	0	229	61
Router	Optimized	cli	no	259	8	68	0	0	267	68
End Device	Optimized	cli	no	199	8	60	0	0	207	60

Flash and RAM requirements for nRF52811

The following tables list flash memory and RAM requirements for the RCP application compiled with typical options using the GCC compiler with size optimization. The values may change depending on the application.

The values in the tables are provided for the RCP example which is a typical use case for nRF52811. For this reason, these values are the best approximation of the memory requirements.