ESP8266 Community Forum

- Wed Mar 30, 2016 7:16 am #44515 Hi Dan,

The receiver side is just a host PC - I've been using tcpdump to watch the incoming traffic :

Code: Select all$ tcpdump -i eth0 -nn udp and port 8989 -s0 -X


If I want to hear the output, I use '-w myfile.pcap' instead of '-X', and then open that pcap file with Wireshark, strip off the IP headers leaving 8-bit unsigned PCM audio that I import into Audacity to play.

This is very clumsy, and I decided to leave it like that until I was happy with the ESP8266 sender side (e.g. I still want to include a camera). Plenty of work still to do

** Actually one of the reasons I was trying to use Timer0 was because I knew ESP8266 uses Timer1 for PWM, and I might have wanted to generate audio using PWM **

- Fri May 20, 2016 7:38 am #47713 Did you test it without using the network inside the interrupt handler? I don't know the internals of the ESP HW and FW architecture, but it might not be safe to do it (I'm not saying it isn't, and for sure there are here users that could clarify this). I'll test it reading the ADC inside the interrupt handler, and sending the data in the main loop.

Best regards

Fernando

- Fri May 20, 2016 7:55 am #47715 Hi, as a side note, the size of UDP packets is limited by 'pbuf_unit_size = 512;' in 'UdpContext.h'. I had to up this to 1024 as I needed to send E1.31 (sCAN DMX) packets which are 638 bytes + the standard 42 for the header. I'm not sure what the maximum size for 'pbuf_unit_size' is or the implications. But it's working for me and dont appear to have had any packets split up yet.