CONFIG_BT=y
CONFIG_BT_SMP=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DIS=y
CONFIG_BT_DIS_PNP=n
CONFIG_BT_BAS=y
CONFIG_BT_HRS=y
CONFIG_BT_DEVICE_NAME="Zephyr Heartrate Sensor"
CONFIG_BT_DEVICE_APPEARANCE=833

# Drivers and peripherals
CONFIG_I2C=n
CONFIG_WATCHDOG=n
CONFIG_PINCTRL=n
CONFIG_SPI=n
CONFIG_GPIO=n
CONFIG_SERIAL=n

# Power management
CONFIG_PM=n

# Interrupts
CONFIG_DYNAMIC_INTERRUPTS=n
CONFIG_IRQ_OFFLOAD=n

# Memory protection
CONFIG_THREAD_STACK_INFO=n
CONFIG_THREAD_CUSTOM_DATA=n
CONFIG_FPU=n

# Boot
CONFIG_BOOT_BANNER=n
CONFIG_BOOT_DELAY=0

# Console
CONFIG_CONSOLE=n
CONFIG_UART_CONSOLE=n
CONFIG_STDOUT_CONSOLE=n
CONFIG_PRINTK=n
CONFIG_EARLY_CONSOLE=n

# Build
CONFIG_SIZE_OPTIMIZATIONS=y

# ARM
CONFIG_ARM_MPU=n

# In order to correctly tune the stack sizes for the threads the following
# Configurations can enabled to print the current use:
# CONFIG_THREAD_NAME=y
# CONFIG_THREAD_ANALYZER=y
# CONFIG_THREAD_ANALYZER_AUTO=y
# CONFIG_THREAD_ANALYZER_RUN_UNLOCKED=y
# CONFIG_THREAD_ANALYZER_USE_PRINTK=y
# CONFIG_THREAD_ANALYZER_AUTO_INTERVAL=20
# CONFIG_CONSOLE=y
# CONFIG_UART_CONSOLE=y
# CONFIG_SERIAL=y
# CONFIG_PRINTK=y

# Example output of thread analyzer
# BT RX               : STACK: unused 576 usage 448 / 1024 (43 %); CPU: 0 %
# BT RX pri           : STACK: unused 260 usage 188 / 448 (41 %); CPU: 0 %
# BT ECC              : STACK: unused 256 usage 888 / 1144 (77 %); CPU: 1 %
# BT TX               : STACK: unused 296 usage 344 / 640 (53 %); CPU: 0 %
# thread_analyzer     : STACK: unused 128 usage 384 / 512 (75 %); CPU: 1 %
# sysworkq            : STACK: unused 856 usage 168 / 1024 (16 %); CPU: 0 %
# logging             : STACK: unused 232 usage 536 / 768 (69 %); CPU: 0 %
# idle 00             : STACK: unused 208 usage 48 / 256 (18 %); CPU: 97 %
# main                : STACK: unused 576 usage 448 / 1024 (43 %); CPU: 0 %
CONFIG_BT_RX_STACK_SIZE=1024
CONFIG_BT_HCI_TX_STACK_SIZE_WITH_PROMPT=y
CONFIG_BT_HCI_TX_STACK_SIZE=640
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=512
CONFIG_IDLE_STACK_SIZE=128
CONFIG_MAIN_STACK_SIZE=640
CONFIG_ISR_STACK_SIZE=1024

# Disable features not needed
CONFIG_TIMESLICING=n
CONFIG_COMMON_LIBC_MALLOC=n
CONFIG_LOG=n
CONFIG_ASSERT=n

# Disable Bluetooth features not needed
# CONFIG_BT_DEBUG_NONE=y
CONFIG_BT_ASSERT=n
CONFIG_BT_DATA_LEN_UPDATE=n
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_ACL_RX_COUNT=2
CONFIG_BT_BUF_EVT_RX_COUNT=2

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