[AT Release] ESP8266_AT_V1.0 based on ESP8266_NONOS_SDK_V1.5.3

[ESP_Faye]

ESP8266_AT_v1.0 Release based on ESP8266_NONOS_SDK_V1.5.3

1. Use Espressif official Flash Download Tool to download AT firmware bin files into Flash according to the at\readme which is in the attachment.
   

   Notice:
   1. Firmware upgrade through WiFi (AT+CIUPDATE) is not supported in non-boot mode.
   2. 4Mbit Flash is not supported in both non-boot mode and with-boot mode.
   

2. Firmware upgrade over-the-air process is changed a bit. We will upgrade the latest AT firmware to Espressif Cloud server only after it has been tested and the overall performance is guaranteed. Users may not be able to use AT+CIUPDATE in ESP8266_NONOS_SDK_V1.5.0 and other more advanced versions.

Important Links
Here are the links for this AT release (version ESP82566_AT_v1.0 based on ESP8266_NONOS_SDK_V1.5.3):

1. ESP8266_NONOS_SDK_V1.5.3
2. AT Commands Documentation
3. Bug Bounty Program

Release Notes
Optimization:

1. Revised the flash map of AT firmware in no boot mode, please download the bin files according to at\readme.
2. Revised the problem that AT+PING may fail when using some special router.
3. Optimized AT firmware when receiving TCP data with UART flow control.

Added AT commands:

1. AT+CIPDOMAIN: for DNS function.

Have fun!

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ESP8266_AT_v1.0 发布，基于 ESP8266_NONOS_SDK_V1.5.3

1. 请使用 Espressif 官方 Flash Download Tool，参考附件压缩包中的 \at\readme 烧录 AT 固件到 Flash 中。
   

   注意：
   

   1. non-boot 模式不支持升级功能 (AT+CIUPDATE)。
   2. AT 固件的 non-boot 模式和 with-boot 模式均不支持 4Mbit Flash。

2. 我司优化了 AT 固件的升级流程 (AT+CIUPDATE)，AT 固件发布后，等待一段时间，待客户反馈稳定后，才上传到 Espressif Cloud 以供下载更新。因此，如果使用 ESP8266_NONOS_SDK_V1.5.0 及之后版本的 AT 固件暂时无法从 Espressif Cloud 升级。

相关下载

以下是最新 SDK 的相关下载链接 (版本 ESP8266_AT_v1.0 基于 ESP8266_NONOS_SDK_V1.5.3):

1. ESP8266_NONOS_SDK_V1.5.3。
2. AT 文档下载链接。
3. 您可以继续参与 Bug Bounty 计划。

发布说明
优化:

1. 调整 no boot 模式 AT bin 的 flashmap，参考 at\readme 文件烧录。
2. 修正部分路由器 AT+PING 失败的问题。
3. 优化当使用 UART 硬件流控时，动态分配空间用于保存网络数据。

新增 AT 指令:

1. 新增指令 AT+CIPDOMAIN，用于进行域名解析。

感谢您对 ESP8266 的关注！