Dear DevZone support team
I'm facing the following problem:
My application uses the Zephyr's BLE stack and basically does not much beside parsing JSON-messages received via BLE and passing them over UART to a second MCU and vice versa.
So it's basically a relays, which enables connecting via BLE and serves another MCU (however, the latter is required for safety reasons).
The current build is surprisingly high, despite the fact, that the Zephyr RTOS and it's BLE stack are involved, most of the flash space is not occupied by the custom application code itself.
Thus, I tried to optimize the code size, but it seems that it's already as small as it can get with the limited / disabled debugging support. However, the "debug information" is still visible in the .map file. Could it be, that it is just treated as optional "filler" in case there's is some available flash space left?
I'm using the following configurationin "prj.conf":
CONFIG_UART_ASYNC_API=yCONFIG_SERIAL=yCONFIG_GPIO=yCONFIG_NRFX_UARTE0=y # This will also enable NRFX_UARTECONFIG_UART_0_NRF_TX_BUFFER_SIZE=64
CONFIG_UART_0_NRF_HW_ASYNC=yCONFIG_UART_0_NRF_HW_ASYNC_TIMER=4CONFIG_NRFX_TIMER=yCONFIG_NRFX_TIMER4=yCONFIG_NRFX_PPI=y
# Use RTT as Console, not UART -> printk are directed to RTT ViewerCONFIG_CONSOLE=yCONFIG_PRINTK=yCONFIG_RTT_CONSOLE=yCONFIG_USE_SEGGER_RTT=yCONFIG_UART_CONSOLE=n
CONFIG_HEAP_MEM_POOL_SIZE=4096
CONFIG_MAIN_STACK_SIZE=11000CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
CONFIG_HW_STACK_PROTECTION=y # Catch Stackoverflow
CONFIG_BT=yCONFIG_BT_LL_SW_SPLIT=yCONFIG_BT_PERIPHERAL=yCONFIG_BT_SETTINGS=yCONFIG_BT_SETTINGS_CCC_STORE_ON_WRITE=yCONFIG_BT_DEVICE_NAME_DYNAMIC=yCONFIG_BT_DEVICE_APPEARANCE=967CONFIG_BT_MAX_CONN=1CONFIG_BT_MAX_PAIRED=2CONFIG_BT_CTLR_TX_PWR_PLUS_4=y # Choose max Tx PowerCONFIG_BT_PHY_UPDATE=nCONFIG_BT_DEVICE_NAME_MAX=10
CONFIG_BT_WHITELIST=yCONFIG_BT_CTLR_FILTER=y # This is enabled in default
# Enable bonding: Flash required, to store permanentlyCONFIG_FLASH=yCONFIG_FLASH_PAGE_LAYOUT=yCONFIG_FLASH_MAP=yCONFIG_NVS=yCONFIG_SETTINGS=yCONFIG_BT_BONDABLE=y # This is enabled in default
# Enable the NUS serviceCONFIG_BT_NUS=yCONFIG_BT_DEBUG_MONITOR=nCONFIG_BT_DEBUG_ATT=n # Will log stuff related to ATT / GATTCONFIG_BT_DEBUG_GATT=nCONFIG_BT_SMP=yCONFIG_BT_SMP_ALLOW_UNAUTH_OVERWRITE=yCONFIG_BT_DEBUG_LOG=n # Will also print stack size for bluetooth thread
# Connection ParameterCONFIG_BT_CREATE_CONN_TIMEOUT=60# Connection Interval in 1.25ms unitsCONFIG_BT_PERIPHERAL_PREF_MIN_INT=24CONFIG_BT_PERIPHERAL_PREF_MAX_INT=40CONFIG_BT_PERIPHERAL_PREF_SLAVE_LATENCY=0CONFIG_BT_PERIPHERAL_PREF_TIMEOUT=2000# Parameter update timeout in msCONFIG_BT_CONN_PARAM_UPDATE_TIMEOUT=5000# Debug LoggingCONFIG_BT_DEBUG_CONN=nCONFIG_BT_DEBUG_SETTINGS=nCONFIG_BT_NUS_LOG_LEVEL_DBG=nCONFIG_BT_DEBUG_HCI_CORE=n
# Enable DK LED and Buttons libraryCONFIG_DK_LIBRARY=y
# sscanf is not supported in zephyr minimal libcCONFIG_NEWLIB_LIBC=y
CONFIG_BT_RX_BUF_LEN=255CONFIG_BT_ATT_TX_MAX=10CONFIG_BT_ATT_PREPARE_COUNT=2CONFIG_BT_CONN_TX_MAX=10CONFIG_BT_L2CAP_TX_BUF_COUNT=10CONFIG_BT_L2CAP_TX_MTU=247CONFIG_BT_L2CAP_RX_MTU=247CONFIG_BT_L2CAP_DYNAMIC_CHANNEL=yCONFIG_BT_CTLR_RX_BUFFERS=2CONFIG_BT_CTLR_TX_BUFFERS=10CONFIG_BT_CTLR_TX_BUFFER_SIZE=251CONFIG_BT_CTLR_DATA_LENGTH_MAX=251
CONFIG_ADC=yCONFIG_ADC_ASYNC=y
CONFIG_I2C=y
# Enable monitoringCONFIG_INIT_STACKS=nCONFIG_THREAD_MONITOR=n # Disabled for testingCONFIG_OBJECT_TRACING=n
# Enable PWMCONFIG_PWM=yCONFIG_NRFX_PWM1=yCONFIG_NRFX_PWM2=y
# FOTACONFIG_MCUMGR=y # Enable mcumgr.CONFIG_BOOTLOADER_MCUBOOT=y # Ensure an MCUboot-compatible binary is generated.
#CONFIG_DEBUG=n#CONFIG_DEBUG_INFO=nCONFIG_DEBUG_OPTIMIZATIONS=n # For better debugging#CONFIG_SIZE_OPTIMIZATIONS=y
CONFIG_NFCT_PINS_AS_GPIOS=y # Disabling this option will not switch back pins to NFCT mode (UICR erase required)CONFIG_SOC_LOG_LEVEL_DBG=n
# Power ManagementCONFIG_DEVICE_POWER_MANAGEMENT=yCONFIG_SYS_POWER_MANAGEMENT=yCONFIG_SYS_POWER_DEEP_SLEEP_STATES=yCONFIG_SYS_PM_STATE_LOCK=y
CONFIG_BOOT_BANNER=n # Reduces footprint size
So, with this configuration the following build output is generated:
1> Linking ‘zephyr_prebuilt.elf’1> Memory region Used Size Region Size %age Used1> FLASH: 222500 B 232960 B 95.51%1> SRAM: 59634 B 64 KB 90.99%1> IDT_LIST: 184 B 2 KB 8.98%
As apparent, the avaliable flash region size is given with 232960 B (227.5kB) which exceeds the forseen partition size according to nrf52dk_nrf52832.dts:
&flash0 { /* * For more information, see: * docs.zephyrproject.org/.../legacy-macros.html */ partitions { compatible = "fixed-partitions"; #address-cells = <1>; #size-cells = <1>;
boot_partition: partition@0 { label = "mcuboot"; reg = <0x00000000 0xc000>; }; slot0_partition: partition@c000 { label = "image-0"; reg = <0x0000C000 0x32000>; }; slot1_partition: partition@3e000 { label = "image-1"; reg = <0x0003E000 0x32000>; }; scratch_partition: partition@70000 { label = "image-scratch"; reg = <0x00070000 0xa000>; }; storage_partition: partition@7a000 { label = "storage"; reg = <0x0007a000 0x00006000>; }; };};
There the specified partition size for the image is 0x32000 B (200kB). Why is this not matching the flash region size from the build output?
So in the end, I'm able to fit the application which occupies 217kB into the given flash region of 227.5kB, so the MCU will get flashed and also works.
But as soon as i want to upgrade the application via FOTA, it fails (with erratic behavior) and the application ends up being bricked.
This is reasonable, since the 217kB image exceeds the partition size of 200kB.
Long story short, is there a way to somehow bring down the image size? I'm not sure how 217kB can be filled with code for what the application actually does..
Did i miss some important points regarding the project configuration which could help?
FYI: I did not participate the project when it has been setup, the major part of the code base has already existed when I became responsible for its maintenance.
Furthermore, I'm not an expert on Zephyr either and did not have the chance yet to setup a project by myself (including all the learnings).
Thanks for your help!
Best regards
Manuel
