Configuration

Standard Library

The Library Reference is configured at compile time using defines named CONFIG_*. The default configuration includes most functionality, as most application wants that. If an application has special requirements, for example memory constraints, it has to be configured to remove unnecessaray functionality.

Search order

Highest priority first.

Simba build system

  1. Command line as CDEFS_EXTRA="<configuration variable>=<value>".
  2. A file named config.h in the application root folder.
  3. The default configuration file, src/config_default.h.

PlatformIO

  1. The variable build_flags in platformio.ini as build_flags = -D<configuration variable>=<value>.
  2. A file named config.h in the application source folder src.
  3. The default configuration file, src/config_default.h.

Arduino IDE

  1. A file (also called a tab) named config.h in the sketch.
  2. The default configuration file, src/config_default.h.

Variables

All configuration variables are listed below. Their default values are defined in src/config_default.h.

Defines

CONFIG_SYS_CONFIG_STRING 1
CONFIG_SYS_SIMBA_MAIN_STACK_MAX 4096

Main thread stack size for ports with a fixed size main thread stack.

CONFIG_ASSERT 1

Assertions are used to check various conditions during the application execution. A typical usage is to validate function input arguments.

CONFIG_ASSERT_FORCE_FATAL 1

Force all assertions to be fatal.

CONFIG_FATAL_ASSERT 1

Enable fatal assertions, FATAL_ASSERT*().

CONFIG_PANIC_ASSERT 1

Enable panic assertions, PANIC_ASSERT*().

CONFIG_DEBUG 1

Include more debug information.

CONFIG_ADC 0

Enable the adc driver.

CONFIG_ANALOG_INPUT_PIN 0

Enable the analog_input_pin driver.

CONFIG_ANALOG_OUTPUT_PIN 0

Enable the analog_output_pin driver.

CONFIG_CAN 0

Enable the can driver.

CONFIG_CHIPID 0

Enable the chipid driver.

CONFIG_RANDOM 0

Enable the random driver.

CONFIG_DAC 0

Enable the dac driver.

CONFIG_DS18B20 0

Enable the ds18b20 driver.

CONFIG_DS3231 0

Enable the ds3231 driver.

CONFIG_ESP_WIFI 0

Enable the esp_wifi driver.

CONFIG_EXTI 0

Enable the exti driver.

CONFIG_FLASH 0

Enable the flash driver.

CONFIG_I2C 0

Enable the i2c driver.

CONFIG_I2C_SOFT 0

Enable the i2c_soft driver.

CONFIG_MCP2515 0

Enable the mcp2515 driver.

CONFIG_NRF24L01 0

Enable the nrf24l01 driver.

CONFIG_OWI 0

Enable the owi driver.

CONFIG_PIN 0

Enable the pin driver.

CONFIG_PWM 0

Enable the pwm driver.

CONFIG_PWM_SOFT 0

Enable the pwm_soft driver.

CONFIG_SD 0

Enable the sd driver.

CONFIG_SPI 0

Enable the spi driver.

CONFIG_UART 1

Enable the uart driver.

CONFIG_UART_SOFT 0

Enable the uart_soft driver.

CONFIG_USB 0

Enable the usb driver.

CONFIG_USB_DEVICE 0

Enable the usb_device driver.

CONFIG_USB_HOST 0

Enable the usb_host driver.

CONFIG_WATCHDOG 0

Enable the watchdog driver.

CONFIG_MODULE_INIT_RWLOCK 1

Initialize the module at system startup.

CONFIG_MODULE_INIT_FS 1

Initialize the fs module at system startup.

CONFIG_MODULE_INIT_SETTINGS 1

Initialize the settings module at system startup.

CONFIG_MODULE_INIT_STD 1

Initialize the std module at system startup.

CONFIG_MODULE_INIT_SEM 1

Initialize the sem module at system startup.

CONFIG_MODULE_INIT_TIMER 1

Initialize the timer module at system startup.

CONFIG_MODULE_INIT_LOG 1

Initialize the log module at system startup.

CONFIG_MODULE_INIT_CHAN 1

Initialize the chan module at system startup.

CONFIG_MODULE_INIT_THRD 1

Initialize the thrd module at system startup.

CONFIG_MODULE_INIT_ADC 0

Initialize the adc driver module at system startup.

CONFIG_MODULE_INIT_ANALOG_INPUT_PIN 0

Initialize the analog_input_pin driver module at system startup.

CONFIG_MODULE_INIT_ANALOG_OUTPUT_PIN 0

Initialize the analog_output_pin driver module at system startup.

CONFIG_MODULE_INIT_CAN 0

Initialize the can driver module at system startup.

CONFIG_MODULE_INIT_CHIPID 0

Initialize the chipid driver module at system startup.

CONFIG_MODULE_INIT_RANDOM 0

Initialize the random driver module at system startup.

CONFIG_MODULE_INIT_DAC 0

Initialize the dac driver module at system startup.

CONFIG_MODULE_INIT_DS18B20 0

Initialize the ds18b20 driver module at system startup.

CONFIG_MODULE_INIT_DS3231 0

Initialize the ds3231 driver module at system startup.

CONFIG_MODULE_INIT_ESP_WIFI 0

Initialize the esp_wifi driver module at system startup.

CONFIG_MODULE_INIT_EXTI 0

Initialize the exti driver module at system startup.

CONFIG_MODULE_INIT_FLASH 0

Initialize the flash driver module at system startup.

CONFIG_MODULE_INIT_I2C 0

Initialize the i2c driver module at system startup.

CONFIG_MODULE_INIT_I2C_SOFT 0

Initialize the i2c_soft driver module at system startup.

CONFIG_MODULE_INIT_MCP2515 0

Initialize the mcp2515 driver module at system startup.

CONFIG_MODULE_INIT_NRF24L01 0

Initialize the nrf24l01 driver module at system startup.

CONFIG_MODULE_INIT_OWI 0

Initialize the owi driver module at system startup.

CONFIG_MODULE_INIT_PIN 0

Initialize the pin driver module at system startup.

CONFIG_MODULE_INIT_PWM 0

Initialize the pwm driver module at system startup.

CONFIG_MODULE_INIT_PWM_SOFT 0

Initialize the pwm_soft driver module at system startup.

CONFIG_MODULE_INIT_SD 0

Initialize the sd driver module at system startup.

CONFIG_MODULE_INIT_SPI 0

Initialize the spi driver module at system startup.

CONFIG_MODULE_INIT_UART 1

Initialize the uart driver module at system startup.

CONFIG_MODULE_INIT_UART_SOFT 0

Initialize the uart_soft driver module at system startup.

CONFIG_MODULE_INIT_USB 0

Initialize the usb driver module at system startup.

CONFIG_MODULE_INIT_USB_DEVICE 0

Initialize the usb_device driver module at system startup.

CONFIG_MODULE_INIT_USB_HOST 0

Initialize the usb_host driver module at system startup.

CONFIG_MODULE_INIT_WATCHDOG 0

Initialize the watchdog driver module at system startup.

CONFIG_MODULE_INIT_BUS 1

Initialize the bus module at system startup.

CONFIG_MODULE_INIT_INET 1

Initialize the inet module at system startup.

CONFIG_MODULE_INIT_PING 1

Initialize the ping module at system startup.

CONFIG_MODULE_INIT_SOCKET 1

Initialize the socket module at system startup.

CONFIG_MODULE_INIT_NETWORK_INTERFACE 1

Initialize the network_interface module at system startup.

CONFIG_MODULE_INIT_SSL 0

Initialize the ssl module at system startup.

CONFIG_MODULE_INIT_UPGRADE 0

Initialize the upgrade module at system startup.

CONFIG_FS_CMD_DS18B20_LIST 1

Debug file system command to list all DS18B20 sensors on the bus.

CONFIG_FS_CMD_ESP_WIFI_STATUS 0

Debug file system command to print the Espressif WiFi status.

CONFIG_FS_CMD_FS_APPEND 1

Debug file system command to append to a file.

CONFIG_FS_CMD_FS_COUNTERS_LIST 1

Debug file system command to list all counters.

CONFIG_FS_CMD_FS_COUNTERS_RESET 1

Debug file system command to set all counters to zero.

CONFIG_FS_CMD_FS_FILESYSTEMS_LIST 1

Debug file system command to list all registered file systems.

CONFIG_FS_CMD_FS_LIST 1

Debug file system command to list all registered file systems.

CONFIG_FS_CMD_FS_FORMAT 1

Debug file system command to format a file system.

CONFIG_FS_CMD_FS_PARAMETERS_LIST 1

Debug file system command to list all parameters.

CONFIG_FS_CMD_FS_READ 1

Debug file system command to read from a file.

CONFIG_FS_CMD_FS_REMOVE 1

Debug file system command to remove a file.

CONFIG_FS_CMD_FS_WRITE 1

Debug file system command to write to a file.

CONFIG_FS_CMD_I2C_READ 1

Debug file system command to read from a i2c bus.

CONFIG_FS_CMD_I2C_WRITE 1

Debug file system command to write to a i2c bus.

CONFIG_FS_CMD_LOG_LIST 1

Debug file system command to list all log objects.

CONFIG_FS_CMD_LOG_PRINT 1

Debug file system command to create a log entry and print it. Mainly used for debugging.

CONFIG_FS_CMD_LOG_SET_LOG_MASK 1

Debug file system command to set the log mask of a log object.

CONFIG_FS_CMD_NETWORK_INTERFACE_LIST 1

Debug file system command to list all network interfaces.

CONFIG_FS_CMD_PIN_READ 1

Debug file system command to read the current value of a pin.

CONFIG_FS_CMD_PIN_SET_MODE 1

Debug file system command to set the mode of a pin.

CONFIG_FS_CMD_PIN_WRITE 1

Debug file system command to write a value to a pin.

CONFIG_FS_CMD_PING_PING 1

Debug file system command to ping a host.

CONFIG_FS_CMD_SERVICE_LIST 1

Debug file system command to list all services.

CONFIG_FS_CMD_SERVICE_START 1

Debug file system command to start a service.

CONFIG_FS_CMD_SERVICE_STOP 1

Debug file system command to stop a services.

CONFIG_FS_CMD_SETTINGS_LIST 1

Debug file system command to list all settings.

CONFIG_FS_CMD_SETTINGS_READ 1

Debug file system command to read the value of a setting.

CONFIG_FS_CMD_SETTINGS_RESET 1

Debug file system command to reset the settings to their original values.

CONFIG_FS_CMD_SETTINGS_WRITE 1

Debug file system command to write a value to a setting.

CONFIG_FS_CMD_SYS_CONFIG 1

Debug file system command to print the system configuration.

CONFIG_FS_CMD_SYS_INFO 1

Debug file system command to print the system information.

CONFIG_FS_CMD_SYS_UPTIME 1

Debug file system command to print the system uptime.

CONFIG_FS_CMD_SYS_PANIC 1

Debug file system command to force a panic of the system.

CONFIG_FS_CMD_SYS_REBOOT 1

Debug file system command to reboot the system.

CONFIG_FS_CMD_THRD_LIST 1

Debug file system command to list threads’ information.

CONFIG_FS_CMD_THRD_SET_LOG_MASK 1

Debug file system command to set the log mask of a thread.

CONFIG_FS_CMD_UPGRADE_APPLICATION_ENTER 1

Debug file system command to enter the application.

CONFIG_FS_CMD_UPGRADE_APPLICATION_ERASE 1

Debug file system command to erase the application.

CONFIG_FS_CMD_UPGRADE_APPLICATION_IS_VALID 1

Debug file system command to check if the application is valid.

CONFIG_FS_CMD_UPGRADE_BOOTLOADER_ENTER 1

Debug file system command to enter the bootloader.

CONFIG_FS_CMD_USB_DEVICE_LIST 1

Debug file system command to list all USB devices.

CONFIG_FS_CMD_USB_HOST_LIST 1

Debug file system command to list all USB devices connected to the USB host.

CONFIG_FS_PATH_MAX 64

The maximum length of an absolute path in the file system.

CONFIG_MONITOR_THREAD 1

Start the monitor thread to gather statistics of the scheulder.

CONFIG_MONITOR_THREAD_PERIOD_US 2000000

Default period of the monitor thread in microseconds.

CONFIG_PREEMPTIVE_SCHEDULER 0

Use a preemptive scheduler.

CONFIG_PROFILE_STACK 1

Profile the stack usage in runtime. It’s a cheap operation and is recommended to have enabled.

CONFIG_SETTINGS_AREA_SIZE 256

Size of the settings area. This size MUST have the same size as the settings generated by the settings.py script.

CONFIG_SETTINGS_BLOB 1

Enable the blob setting type.

CONFIG_SHELL_COMMAND_MAX 64

Maximum number of characters in a shell command.

CONFIG_SHELL_HISTORY_SIZE 768

Size of the shell history buffer.

CONFIG_SHELL_MINIMAL 0

Minimal shell functionality to minimize the code size of the shell module.

CONFIG_SHELL_PROMPT "$ "

The shell prompt string.

CONFIG_SOCKET_RAW 1

Raw socket support.

CONFIG_SPIFFS 0

SPIFFS is a flash file system applicable for boards that has a reasonably big modifiable flash.

CONFIG_FAT16 1

FAT16 is a file system.

CONFIG_FILESYSTEM_GENERIC 1

Generic file system.

CONFIG_START_CONSOLE CONFIG_START_CONSOLE_UART

Start the console device (UART/USB CDC) on system startup.

CONFIG_START_CONSOLE_DEVICE_INDEX 0

Console device index.

CONFIG_START_CONSOLE_UART_BAUDRATE 38400

Console UART baudrate.

CONFIG_START_CONSOLE_UART_RX_BUFFER_SIZE 32

Console UART baudrate.

CONFIG_START_CONSOLE_USB_CDC_CONTROL_INTERFACE 0

Console USB CDC control interface number.

CONFIG_START_CONSOLE_USB_CDC_ENDPOINT_IN 2

Console USB CDC input endpoint.

CONFIG_START_CONSOLE_USB_CDC_ENDPOINT_OUT 3

Console USB CDC output endpoint.

CONFIG_START_CONSOLE_USB_CDC_WAIT_FOR_CONNETION 1

Wait for the host to connect after starting the console.

CONFIG_START_FILESYSTEM 0

Configure a default file system.

CONFIG_START_FILESYSTEM_ADDRESS 0

Configure a default file system start address.

CONFIG_START_FILESYSTEM_SIZE 65536

Configure a default file system size.

CONFIG_START_NETWORK 0

Setup the ip stack and connect to all configured networks.

CONFIG_START_NETWORK_INTERFACE_WIFI_CONNECT_TIMEOUT 30

WiFi connect timeout is seconds.

CONFIG_START_NETWORK_INTERFACE_WIFI_SSID MyWiFiSSID

SSID of the WiFi to connect to.

CONFIG_START_NETWORK_INTERFACE_WIFI_PASSWORD MyWiFiPassword

Password of the WiFi to connect to.

CONFIG_START_SHELL 1

Start a shell thread communication over the console channels.

CONFIG_START_SHELL_PRIO 30

Shell thread priority.

CONFIG_START_SHELL_STACK_SIZE 768

Shell thread stack size in words.

CONFIG_START_SOAM 0

Start a SOAM thread communication over the console channels.

CONFIG_START_SOAM_PRIO 30

SOAM thread priority.

CONFIG_START_SOAM_STACK_SIZE 840

SOAM thread stack size in words.

CONFIG_STD_OUTPUT_BUFFER_MAX 16

Maximum number of bytes in the print output buffer.

CONFIG_FLOAT 1

Use floating point numbers instead of intergers where applicable.

CONFIG_SYSTEM_TICK_FREQUENCY 100

System tick frequency in Hertz.

CONFIG_SYSTEM_INTERRUPTS 1

Use interrupts.

CONFIG_SYSTEM_INTERRUPT_STACK_SIZE 0

Interrupt stack size in bytes. Set to a value greater than zero to enable the interrupt stack.

CONFIG_THRD_CPU_USAGE 1

Calculate thread CPU usage.

CONFIG_THRD_ENV 1

Each thread has a list of environment variables associated with it. A typical example of an environment variable is “CWD” - Current Working Directory.

CONFIG_THRD_IDLE_STACK_SIZE 1024

Stack size of the idle thread.

CONFIG_THRD_MONITOR_STACK_SIZE 1024

Stack size of the monitor thread.

CONFIG_THRD_SCHEDULED 1

Count the number of times each thread has been scheduled.

CONFIG_THRD_STACK_HEAP 0

Enable the thread stack heap allocator.

CONFIG_THRD_STACK_HEAP_SIZE 0

Size in bytes of the thread stack heap.

CONFIG_THRD_TERMINATE 1

Threads are allowed to terminate.

CONFIG_USB_DEVICE_VID 0x2341

USB device vendor id.

CONFIG_USB_DEVICE_PID 0x8037

USB device product id.

CONFIG_EMACS_COLUMNS_MAX 80

Number of colums in Emacs text editor.

CONFIG_EMACS_ROWS_MAX 24

Number of rows in Emacs text editor.

CONFIG_EMACS_HEAP_SIZE 32768

Heap size of the emacs text editor.

CONFIG_SYSTEM_TICK_SOFTWARE 0

System tick using a software timer instead of a hardware timer. Suitable for ESP8266 to enable software PWM.

CONFIG_HTTP_SERVER_SSL 0

Add support to wrap the HTTP server in SSL, creating a HTTPS server.

CONFIG_HTTP_SERVER_REQUEST_BUFFER_SIZE 128

Size of the HTTP server request buffer. This buffer is used when parsing received HTTP request headers.

CONFIG_CRC_TABLE_LOOKUP 1

Use lookup tables for CRC calculations. It is faster, but uses more memory.

CONFIG_SPC5_BOOT_ENTRY_RCHW 1
CONFIG_SPC5_RAM_CLEAR_ALL 1
CONFIG_TIME_UNIX_TIME_TO_DATE 1

Include the function time_unix_time_to_date().

CONFIG_SOAM_EMBEDDED_DATABASE 0

Embed the SOAM database in the application.

lwIP

Use config.h to fully configure lwIP and all of its modules. You do not need to define every option that lwIP provides; if you do not define an option, a default value will be used. Therefore, your config.h provides a way to override much of the behavior of lwIP.

By default Simba overrides a few of the variables in src/inet/lwipopts.h.

Module support (Code size)

Enabling and disabling modules

You can tune your code size by only compiling the features you really need. The following is a list of what gets compiled in “out of the box” with lwIP.

Default inclusions:

  • ARP (LWIP_ARP)
  • IP and fragmentation (IP_FRAG) and reassembly (IP_REASSEMBLY)
  • Raw IP PCB support (LWIP_RAW)
  • UDP (LWIP_UDP) and UDP-Lite (LWIP_UDPLITE)
  • TCP (LWIP_TCP) – this is a big one!
  • Statistics (LWIP_STATS)

Default exclusions:

  • DHCP (LWIP_DHCP)
  • AUTOIP (LWIP_AUTOIP)
  • SNMP (LWIP_SNMP)
  • IGMP (LWIP_IGMP)
  • PPP (PPP_SUPPORT)

If you would like to change this, then you just need to set the options listed below. For example, if you would like to disable UDP and enable DHCP, the following config.h file would do it:

/* Disable UDP */
#define LWIP_UDP 0

/* Enable DHCP */
#define LWIP_DHCP 1

Memory management (RAM usage)

Memory pools

In an embedded environment, memory pools make for fast and efficient memory allocation. lwIP provides a flexible way to manage memory pool sizes and organization.

lwIP reserves a fixed-size static chunk of memory in the data segment, which is subdivided into the various pools that lwip uses for the various data structures. For example, there is a pool just for struct tcp_pcb’s, and another pool just for struct udp_pcb’s. Each pool can be configured to hold a fixed number of data structures; this number can be changed in the config.h file by changing the various MEMP_NUM_* values. For example, MEMP_NUM_TCP_PCB and MEMP_NUM_UDP_PCB control the maximum number of tcp_pcb and udp_pcb structures that can be active in the system at any given time.

It is also possible to create custom memory pools in addition to the standard ones provided by lwIP.

Dynamic allocation: mem_malloc

lwIP uses a custom function mem_malloc for all dynamic allocation; therefore, it is easy to change how lwIP uses its RAM. There are three possibilities provided out-of-the-box:

  1. (default) lwIP’s custom heap-based mem_malloc. By default, lwIP uses a statically-allocated chunk of memory like a heap for all memory operations. Use MEM_SIZE to change the size of the lwIP heap.
  2. C standard library malloc and free. If you wish to have lwIP use the standard library functions provided by your compiler/architecture, then define the option MEM_LIBC_MALLOC.
  3. Memory pools. lwIP can also emulate dynamic allocation using custom memory pools (see that chapter for more information). This involves the options MEM_USE_POOLS and MEMP_USE_CUSTOM_POOLS and a new custom file lwippools.h.

Understanding/changing memory usage

lwIP uses memory for:

  • code (depending on your system, may use ROM instead of RAM)

  • statically allocated variables (some initialized, some not initialized)

  • task stack

  • dynamically allocated memory

    • heap
    • memp pools

Unless you use a C library heap implementation (by defining MEM_LIBC_MALLOC to 1), dynamically allocated memory must be statically allocated somewhere. This means you reserve a specific amount of memory for the heap or the memp pools from which the code dynamically allocates memory at runtime.

The size of this heap and memp pools can be adjusted to save RAM:

There are 3 types of pbufs:

  • REF/ROM, RAM and POOL. PBUF_POOL_SIZE * PBUF_POOL_BUFSIZE only refers to type POOL.
  • RAM pbufs are allocated in the memory defined by MEM_SIZE (this memory is not used much aside from RAM pbufs) - this is the heap and it is allocated as mem_memory.
  • REF/ROM pbufs as well as pcbs and some other stuff is allocated from dedicated pools per structure type. The amount of structures is defined by the various MEMP_NUM_ defines. Together, this memory is allocated as memp_memory and it includes the pbuf POOL.

However, if you define MEMP_MEM_MALLOC to 1 in your config.h, every piece of dynamically allocated memory will come from the heap (the size of which is defined by MEM_SIZE). If you then even define MEM_LIBC_MALLOC to 1, too, lwIP doesn’t need extra memory for dynamically allocated memory but only uses the C library heap instead. However, you then have to make sure that this heap is big enough to run your application.

To tweak the various MEMP_NUM_ defines, define LWIP_STATS=1 and LWIP_STATS_DISPLAY=1 and call stats_display() to see how many entries of each pool are used (or have a look at the global variable lwip_stats instead).

Fine-tuning even more

To see the options that you can set, open 3pp/lwip-1.4.1/src/include/lwip/opt.h. This file is fully commented and explains how many of the options are used.