The Espressif Wi-Fi solution supports automatic RF calibration mechanism. The auto-calibration function is realized in conjunction with the external hardware components on the Wi-Fi module such as the antenna.
To enhance the reliability of RF performance, a sector containing RF calibration parameters has been added to the SDK since the release of version 1.5.4.1. SDK versions earlier than V1.5.4.1 have the limitation of flash map. It is not clear that which sector of flash is available in users’ systems. Therefore the older SDK versions need to be upgraded. Function “user_rf_cal_sector_set” in the SDK needs to be called to specify the “rf_sector”. Please refer to “2C-ESP8266__SDK_API_Guide” (download here) for more details. In addition, “esp_init_data_default.bin” has been modified in this release.
At the first boot up of SDK, the chip internally performs automatic RF calibration according to the conditions of the peripheral components such as the antenna. The RF calibration parameters will be retained in the predetermined sector. A lack of SDK upgrade would decrease the reliability of RF performance. Espressif strongly recommends that users upgrade the SDK to the latest version and install all the patches. The upgrade will not affect any features developed based on the original SDK.
Please feel free to email feedback@espressif.com for technical inquiries.
Espressif Systems has been dedicated to providing the best products, services and solutions. Thank you all for the continuous support.
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乐鑫 Wi-Fi 方案射频性能支持自动校准功能，并配合 Wi-Fi 模组天线等硬件的细微差异实现自动校准。
为了提高射频性能的稳定性，自 ESP_SDK_V1.5.4.1 开始，新增自校准射频参数系统保存扇区。由于此前 SDK 版本中 Flash map 的限制，以及不确定客户系统中哪个Flash扇区可用，因此所有 SDK 用户必须升级其 SDK 版本，并在 SDK 中调用 “user_rf_cal_sector_set” 函数来指定射频参数系统保存扇区，详细 API 说明见文档《2C-ESP8266__SDK_API_Guide》（下载)。此外，本次更新还对 “esp_init_data_default.bin” 做出了修改。
SDK在初次上电过程中，IC 内部会根据外围硬件天线等条件来做射频性能自动校准，并且SDK会将自校准射频参数保存到设定的扇区，SDK运行过程中的射频性能将取决于保存的自校准射频参数。若不做系统升级，此部分性能优势则不能很好发挥。乐鑫科技建议所有 SDK 用户完成此功能升级，升级 SDK 至最新版本或更新对应版本的 patch。此次升级不会影响客户基于原 SDK 开发的功能，请放心使用。
若有任何疑问，请发送邮件至 feedback@espressif.com。
乐鑫科技一如既往提供优质服务和更好的解决方案，感谢所有用户的支持。
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