Hello,
I am using LWIP stack (2.0.2) with pppos.
I have NXP MC5748 board with SIM800c interface with one UART channel.
I have used AT commands to configure GSM module.
I am trying to send data to server using LWIP socket programming.
Steps of programming:
1. lwip_socket(PF_INET, SOCK_STREAM, 0);
2. lwip_connect(socket_fd,(struct sockaddr_in*)&sa,sizeof(struct sockaddr_in));
3. lwip_write(socket_fd, "test", 4);
After step 3. i am able to send "test" to server,
But in next step i am sending again data to server
And code get stuck in "LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",pcb->unsent_oversize == last_unsent->oversize_left);"
My oberservation while debugging is , After connect call only once system sending data to server and
while sending second time it getting stuck as i mentioned above.
during this condition, last_unsent->oversize_left = 0.
And pcb->unsent_oversize = 124 (When TCP_MSS = 128 and TCP_SND_BUF =256) ,my data length was 4.
I have also tried other values for TCP_MSS and TCP_SND_BUF like 1024 and 2048 respectivly
So please help to sort out this issue, Why code is getting stuck while sending data second time.
And To solve this issue, Do i need to do any specific setting in PPPOS configuration?
Thanks,
Rahul