How would I go about pausing the time (for a game on the AVR microcontroller)

Question

basically I need to implement a pause feature in my game (which is a simplified version of frogger) which stops the logs scrolling, and ignores any other input until the character p is pressed again). The way I've started to implement this in a while loop is to end it once another p Is pressed.

   if(serial_input == 'p' || serial_input == 'P') {
    while(1){

    //need to pause the game

if(serial_input == 'p' || serial_input == 'P')
break;
     }

This is how my logs are currently scrolling: /* The following statements change the scrolling speeds of the individual logs */

            current_time = get_clock_ticks();

    if(is_frog_alive() && current_time >= last_move_time1 + 1000) {
        scroll_lane(0, 1);
        last_move_time1 = current_time;
    } else if(is_frog_alive() && current_time >= last_move_time2 + 600) {
                scroll_lane(1, -1);
                last_move_time2 = current_time;
    } else if(is_frog_alive() && current_time >= last_move_time3 + 800) {
                scroll_lane(2, 1);
                last_move_time3 = current_time;
    } else if(is_frog_alive() && current_time >= last_move_time4 + 900) {
                scroll_log_channel(0, -1);
                last_move_time4 = current_time;
    } else if(is_frog_alive() && current_time >= last_move_time5 + 1200) {
                scroll_log_channel(1, 1);
                last_move_time5 = current_time;

And this is implemented by a timer as described:

* We update a global clock tick variable - whose value
* can be retrieved using the get_clock_ticks() function.
*/

Any suggestions would be greatly appreciated

Answer 1

I've always used interrupts for handling key presses through the usart.

Have something like this. Just remember to initialise it as per the requirements in your chip's datasheet.

ISR(USART0_RX_vect)  //or USART1 if it's usart 1
{
    uint8_t inByte = UDR0;   //or UDR1 if it's usart 1

    if(inByte == 'P')
    {
        pauseFlag = TRUE; //declare pauseFlag as a global and make it a volatile type
    }
}

Then you can use the pause flag however you want in the main code. Just check it in a switch statement that periodically checks key press flags.