ESP32 Forum

roctwo

A esp32 module, as the WiFi of station, used as the UDP client,used for send data. A esp32 module as the WiFi of the AP,used as the UDP server,used for receive data.Two esp32 modules make up the WiFi LAN, not the extranet.And there are no other devices in this network.I have already set the maximum ...

roctwo

Code: Select all

ret=sendto(sock,start,SEND_START_LEN,0,(struct sockaddr *)&toAddr,sizeof(toAddr))
if(ret<0)
{
   printf("errno is %d\n",errno);
}
else
{
   printf("send success\n");
}

Data transmission through wifi,using UDP.
Log is：errno is -1.
So my question is:What "errno==-1" indicates based on sendto fails.

roctwo

Have a look at the following: https://linux.die.net/man/2/sendto If we look down to return values it states: On success, these calls return the number of characters sent. On error, -1 is returned, and errno is set appropriately. This means that sendto() returns the number of characters sent and not...

roctwo

For some reasons,the matching network was canceled by designer,this wasn't followed the reference design of ESP32,and could be lead to some wifi problems.But should not appeared the problem " when the WiFi chanel is 6, the data can not be sent out",cause when wifi channel is 1 or 11,the data can be ...

roctwo

Data transmission through wifi,using UDP,call sendto API.errno is -1.What "errno==-1" indicates?From errno.h,every macro of errno is positive number.

roctwo

IDF version is v2.0.Chip is D2WD.Hardware is designed by ourself. The attachment is part of our hardware design. Based on our hardware design, when the WiFi chanel is 6, the data can not be sent out.The fail reason is ENOMEM.Based on esp-wroom-32 module,channel 6 is normal. "When the WiFi chanel is ...

roctwo

I'm using esp32 as sniffer, but it's hard to get the packet I want. can esp32 filter packets through MAC address?

roctwo

hi if we use ESP32-D2WD with embedded Flash we need to be noted that the memory used 1.8 V, right? we can then use the regulator by pullup on MTDI, or burn appropriate efuses using espefuse.py tool $IDF_PATH/components/esptool_py/esptool/espefuse.py set_flash_voltage 1.8V can we use PSRAM32 with th...

roctwo

I see you are configuring some GPIOs... which one do you configure after GPIO10? I see you are configuring some GPIOs... which one do you configure after GPIO10?[/quote] After configure GPIO10.GPIO is not configured any more.After configure GPIO10,"periph_module_enable(PERIPH_I2S0_MODULE)" is calle...

roctwo

Are you sure the on air times and datarates are the same? I am sure dataratesa is same.I don't understand what is "the on air times".The experimental environment is in the air. The time the radio is transmitting. If lower txpower may be more retries or slower bitrates. "the on air times" is same

Search found 95 matches

The reception performance of WiFi?

What "errno==-1" indicates based on sendto fails?Every macro of errno is positive number from "errno.h".

Re: Sendto fail.errno is -1.What "errno==-1" indicates?Every macro of errno is positive number.

Re: Based on our hardware design, when the WiFi chanel is 6, the data can not be sent out.

Sendto fail.errno is -1.What "errno==-1" indicates?Every macro of errno is positive number.

Based on our hardware design, when the WiFi chanel is 6, the data can not be sent out.

ESP32 as promiscuous mode, can esp32 filter packets through MAC address?

Re: ESP32-D2WD with PSRAM32 , SPI Flash , free Pins - rules to be noted -

Re: Look out，I found so many problems with the d2wd！

Re: Is the maximum transmit power greater, the higher the average peak current?

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