Related to tms processor

I am trying to generate a switching pulse directly using GPIO . To generate switching pulse a carrier signal i have used which has a frequency of 9kHZ. Which is only possible at solver step size of 1micro second or less than that. But when i am taking the solver step size of 1e-6 then the processor is responding as the target is not connected ,but when i am taking the step size as 0.5e-6 the processor is running but the gate pulse generated is not proper because the carrier signal is not like the triangular carrier signal it is distorted. So how to solve this problem by changing the step size ..