samples: Bluetooth: peripheral_hr minimal configuration update

Updated peripheral_hr sample to use separate Zephyr
Controller overlay for minimal configuration.

For bbc_microbit:
Memory region         Used Size  Region Size  %age Used
           FLASH:       96268 B       256 KB     36.72%
             RAM:       16296 B        16 KB     99.46%
        IDT_LIST:          0 GB        32 KB      0.00%

For nrf54l15dk/nrf54l15/cpuapp:
Memory region         Used Size  Region Size  %age Used
           FLASH:       95012 B      1428 KB      6.50%
             RAM:       17744 B       188 KB      9.22%
        IDT_LIST:          0 GB        32 KB      0.00%

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>

Author: cvinayak

samples/bluetooth/peripheral_hr/README.rst

@@ -24,4 +24,20 @@ Building and Running
 This sample can be found under :zephyr_file:`samples/bluetooth/peripheral_hr` in the
 Zephyr tree.
 
-See :zephyr:code-sample-category:`bluetooth` samples for details.
+Building a minimal variant
+--------------------------
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/bluetooth/peripheral_hr
+   :board: qemu_cortex_m3
+   :goals: build
+   :gen-args: -DCONF_FILE=prj_minimal.conf
+
+Building a minimal variant for bbc_microbit
+-------------------------------------------
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/bluetooth/peripheral_hr
+   :board: bbc_microbit
+   :goals: build
+   :gen-args: -DCONF_FILE=prj_minimal.conf -DEXTRA_CONF_FILE=overlay-bt_ll_sw_split-minimal.conf

samples/bluetooth/peripheral_hr/overlay-bt_ll_sw_split-minimal.conf

@@ -0,0 +1,15 @@
+# Zephyr open source Bluetooth Low Energy Controller
+CONFIG_BT_LL_SW_SPLIT=y
+
+# Optimizations
+CONFIG_ISR_TABLES_LOCAL_DECLARATION=y
+CONFIG_LTO=y
+
+# Disable Bluetooth controller features not needed
+CONFIG_BT_CTLR_CONN_PARAM_REQ=n
+CONFIG_BT_CTLR_EXT_REJ_IND=n
+CONFIG_BT_CTLR_PER_INIT_FEAT_XCHG=n
+CONFIG_BT_CTLR_MIN_USED_CHAN=n
+
+# Buffer sizes
+CONFIG_BT_CTLR_RX_BUFFERS=1

samples/bluetooth/peripheral_hr/prj_minimal.conf

@@ -44,6 +44,7 @@ CONFIG_SIZE_OPTIMIZATIONS=y
 
 # ARM
 CONFIG_ARM_MPU=n
+CONFIG_BUILTIN_STACK_GUARD=n
 
 # In order to correctly tune the stack sizes for the threads the following
 # Configurations can enabled to print the current use:
@@ -91,20 +92,14 @@ CONFIG_BT_PHY_UPDATE=n
 CONFIG_BT_GATT_CACHING=n
 CONFIG_BT_GATT_SERVICE_CHANGED=n
 CONFIG_BT_GAP_PERIPHERAL_PREF_PARAMS=n
-CONFIG_BT_SETTINGS_CCC_LAZY_LOADING=y
 CONFIG_BT_HCI_VS=n
 
-# Disable Bluetooth controller features not needed
-CONFIG_BT_CTLR_PRIVACY=n
-CONFIG_BT_CTLR_PHY_2M=n
-
 # Reduce Bluetooth buffers
 CONFIG_BT_BUF_EVT_DISCARDABLE_COUNT=1
 CONFIG_BT_BUF_EVT_DISCARDABLE_SIZE=45
 CONFIG_BT_BUF_EVT_RX_COUNT=4
 
 CONFIG_BT_L2CAP_TX_BUF_COUNT=2
-CONFIG_BT_CTLR_RX_BUFFERS=1
 CONFIG_BT_BUF_ACL_TX_COUNT=3
 CONFIG_BT_BUF_ACL_TX_SIZE=27
 

samples/bluetooth/peripheral_hr/sample.yaml

@@ -30,12 +30,27 @@ tests:
     tags: bluetooth
     sysbuild: true
   sample.bluetooth.peripheral_hr.minimal:
+    harness: bluetooth
+    platform_allow:
+      - qemu_cortex_m3
+    integration_platforms:
+      - qemu_cortex_m3
+    extra_args:
+      - CONF_FILE=prj_minimal.conf
+    tags: bluetooth
+  sample.bluetooth.peripheral_hr.bt_ll_sw_split.minimal:
     harness: bluetooth
     platform_allow:
       - bbc_microbit
+      - nrf52dk/nrf52832
+      - nrf54l15dk/nrf54l15/cpuapp
     integration_platforms:
       - bbc_microbit
-    extra_args: EXTRA_CONF_FILE=prj_minimal.conf
+      - nrf52dk/nrf52832
+      - nrf54l15dk/nrf54l15/cpuapp
+    extra_args:
+      - CONF_FILE=prj_minimal.conf
+      - EXTRA_CONF_FILE=overlay-bt_ll_sw_split-minimal.conf
     tags: bluetooth
   sample.bluetooth.peripheral_hr.bt_ll_sw_split.extended:
     harness: bluetooth