WiFi

setCountryCode() [WiFi]

Note:

// PROTOTYPE
int setCountryCode(wlan_country_code_t country_code);

By default, Wi-Fi devices use the United States channel plan, which is the most restrictive of channel plans for Wi-Fi. The most noticeable effect of this is that devices will not use channel 2.4 GHz Wi-Fi channel 12, which has restrictions in the United States that make its use impractical in many cases, so it's just disabled.

You can set the Wi-Fi country code from C++ code running on the device using:

WiFi.setCountryCode(WLAN_CC_AU); // Australia

• This only sets a value in the DCT (configuration flash).
• It is persistent, and not reset when flashing user firmware, Device OS, clear credentials, or Device Restore.
• You must call it before connecting to Wi-Fi, which can be accomplished in several ways:
  • Call it from your one-time setup or test firmware, since the setting is persistent (recommended).
  • Use SYSTEM_MODE(SEMI_AUTOMATIC) and set the country code before Particle.connect().
  • Call it from STARTUP().

The following country codes are defined:

typedef enum wlan_country_code_t {
    WLAN_CC_UNSET = 0x0000,
    WLAN_CC_US = 0x5553,
    WLAN_CC_EU = 0x4555,
    WLAN_CC_JP = 0x4A50,
    WLAN_CC_CA = 0x4341,
    WLAN_CC_MX = 0x4D58,
    WLAN_CC_GB = 0x4742,
    WLAN_CC_AU = 0x4155,
    WLAN_CC_KR = 0x4B52,
    WLAN_CC_WORLD = 0xFFFE,
    WLAN_CC_MAX = 0xFFFF
} wlan_country_code_t;

The data is stored in the DCT at DCT_COUNTRY_CODE_OFFSET (1758) as two bytes in big-endian order (high byte first). This is the implementation of the underlying function which shows how it's actually written to the configuration flash.

int wlan_set_country_code(wlan_country_code_t country_code, void* reserved) {
    char cc_buf[2] = { (char)(country_code >> 8),  (char)(country_code & 0xFF) };
    return dct_write_app_data(cc_buf, DCT_COUNTRY_CODE_OFFSET, sizeof(cc_buf));
}

Because the setting is stored in the DCT, it's possible to set the value in DFU mode. You can do so using dfu-util with the -a 1 (alt bank 1) option.

The DCT on Gen 3 and Gen 4 devices is stored in a file on the file system, so it is impractical to set the value by SWD/JTAG.