I would suggest using delays. I know this is a bad word but I think, at least to get you going it would be the best way.
I'm not great with code but essentially you would:
- Setup up a timer for 8kHz
- Turn on the timer
- delay(12)
- delaymicroseconds(500)
- turn off the timer
- delay(12)
- delaymicroseconds(500)
Loop forever