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RL-ARM User's Guide (MDK v4)

RL-RTX RL-FlashFS RL-TCPnet TCP Socket Opening TCP Connection TCP Active Open TCP Passive Open Sending TCP Data Example for Sending Data Multiple TCP Connections UDP Socket Opening UDP Connection Sending UDP Data When DHCP Enabled When ARP Cache Empty Example for Sending Data IP Multicasting Multiple UDP Connections Configuring RL-TCPnet Static Configuration System Definitions Ethernet Network Interface PPP Network Interface SLIP Network Interface UDP Socket TCP Socket BSD Socket HTTP Server Telnet Server TFTP Server TFTP Client FTP Server FTP Client DNS Client SMTP Client SNMP Agent SNTP Client Error Function Runtime Configuration Library Files Using RL-TCPnet Stand Alone With RTX Kernel Event Driven Operation IP Address Assignment Ethernet Interface PPP Interface SLIP Interface Localhost Applications HTTP Server Script Language CGI Functions Ajax Support Using XML XML Example How it works SOAP Support SOAP Interface Large POST Messages Web Pages Default Page Error Pages Web on SD Card Web Update File System Interface Http Caching How it works Internal Web External Web Multi-user Authentication Using RAM File System FCARM File Converter PRINT Directive NOPRINT Directive PAGEWIDTH Directive PAGELENGTH Directive ROOT Directive Telnet Server Command Line Interface Multi-user Authentication Sending Reply Message Short Reply Long Reply Continuous Screen Update TFTP Server File System Interface TFTP Client File System Interface FTP Server File System Interface Multi-user Authentication Supported Commands FTP Client File System Interface SMTP Client SNMP Agent MIB Database MIB Interface MIB Entry MIB Table DNS Resolver Starting DNS Device Drivers Ethernet Driver Interrupt Mode Modem Driver Serial Driver Using Serial Link Cable Connection Modem Connection Windows Dial-up Add Direct Serial Link New Dial-up Connection Configure PPP Dial-up Configure SLIP Dial-up Debugging Enabling Debug Debug Level Redirecting Output Function Overview BSD Routines CGI Routines Ethernet Routines FTP Routines HTTP Routines IGMP Routines Miscellaneous Routines Modem Routines PPP Routines Serial Routines SLIP Routines SMTP Routines SNMP Routines System Functions TCP Routines Telnet Routines TFTP Routines UDP Routines RL-CAN RL-USB Example Programs Library Reference Appendix

Event Driven Operation

The event-driven operation of RL-TCPnet allows you to run TCPnet application in event-driven mode in a multitasking environment. Instead of calling the polling loop constantly, the system processess TCPnet events only when needed. The rest of time, TCPnet system remains idle.

The main_TcpNet() function is modified to return a busy status indication. If TCPnet system is busy, this function has to be called again, to complete the TCP/IP processing. If TCPnet is not busy, TCP/IP processing might be stalled, until a TCPnet event occurs.

The TCPnet events, which require TCP/IP processing, are:

  • ethernet packet received,
  • tick timer interval expired,
  • serial character received or transmitted.

Event-driven operation optimizes the cpu usage a lot. The following table lists the cpu time required for TCP/IP processing and cpu idle time for HTTP_Demo example:

TCP/IP processing System Idle time
247 ms 85953 ms

In order to modify the TCPnet application for event-driven operation, you must make the following changes to your project:

  • ethernet driver
    Add the code to send a signal event to tcp_main task in the ethernet receive interrupt function.
    static void interrupt_ethernet (void) __irq {
      fetch_packet ();
      isr_evt_set(0x0001, tcp_task);
  • tcp_tick task
    Add the code to send a signal event to tcp_main task. The priority of the tcp_tick task should be higher than the priority of tcp_main task.
    __task void tcp_tick (void) {
      os_itv_set (10);
      while (1) {
        os_itv_wait ();
        timer_tick ();
        os_evt_set(0x0001, tcp_task);
  • tcp_main task
    Add the code to wait for an event in TCPnet tcp_main task. The priority of tcp_main task should be higher than the application layer / service layer tasks.
    __task void tcp_main (void) {
      init_TcpNet ();
      while (1) {
        os_evt_wait_and(0x0001, 0xFFFF);
        while (main_TcpNet() == __TRUE);
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