Serial Port Complete - Latest Microcontroller projects

An RS-485 Network

If delay_before_responding isn’t defined, the timer never starts and communi-

cations never enter the “d” state.

 prepare_to_respond:

response_index = 0;

if (delay_before_responding = 1) then

gosub start_response_delay_timer

network_state = "d"

else

network_state = "t"

endif

return

 void prepare_to_respond(void)
{
response_index = 0;
#if defined(delay_before_responding)
start_response_delay_timer();
network_state = 'd';
#else
network_state = 't';
#endif
}
The start_response_delay_timer function initializes and starts the timer.

 start_response_delay_timer:

' This example sets a delay of around 0.5 second assuming FOSC = 4 MHz.

' Timer enabled, 16-bit, internal clock, prescaler = 256.

T0CON = $87

' Load the timer with F800h.

TMR0L = $00

TMR0H =$F8

return