Can ESP-NOW improve this situation? If so, i am interested in it, and what are the requirements for the MQTT server? As the MQTT server belongs to the operator,and can not be changed.

我发现MQTT启动太慢:从调用esp_mqtt_client_start()函数，到返回连接成功，这个过程耗时7秒钟左右。我让服务器端工程师翻查一下登录日志，结果发现从登录连接开始到登录成功只需要花不到1秒钟。也就是说有6秒钟花在MQTT模块自身的初始化上。请问一下这种情况有办法优化一下吗:让整个过程耗时缩短。

When esp_mqtt_client_start was caleed,it takes 7 seconds to return connected state.Then I found that it took less than 1 second to connect from the beginning to return OK. Is there any way to shorten the time ahead?

我用ESP32-S2FN4R2芯片设计出来的板焊上ESP32-S2FN4R2后烧录不了，已经换过2片芯片了还是烧录不了，不知道是什么原因：IO0上电前已经接地了，IO18上电前也已经上拉10K电阻了，烧录脚是48、49脚（U0RXD,U0TXD）,56脚也已经上拉高电平了。而我之前购买的ESP32-S2模组设计出来的板就能烧录。

想要连接USB CAM，怎么获取到usb driver呢

board:esp32+sim800c,demo:Pppos_client,i found a problem:modem stopped after recieved a pcket,that will happen every time.This confused me. Is sim800c can't fit this demo? Can someone give some advice?here is the log: start up: [0;32mI (1141) pppos_example: GOT ip event!!![0m [0;32mI (1151) pppos_exa...

环境是ESP32+SIM800C的硬件，运行的是Pppos client_main的例子。发现每次接收到MQTT下发的命令后，modem就断开了。如下的log: [0;32mI (1141) pppos_example: GOT ip event!!![0m [0;32mI (1151) pppos_example: PPP state changed event 266[0m [0;32mI (1161) pppos_example: MQTT other event id: 7[0m 【2021-11-10 13:45:41:738】[0;32mI (2451) pppos_example...