diff --git a/cubesatsim/cubesatsim.ino b/cubesatsim/cubesatsim.ino
index 9aa05b91..667105d0 100644
--- a/cubesatsim/cubesatsim.ino
+++ b/cubesatsim/cubesatsim.ino
@@ -2253,7 +2253,7 @@ void start_pwm() {
   set_sys_clock_khz(133000, true); 	
   gpio_set_function(BPSK_PWM_PIN, GPIO_FUNC_PWM);
 
-  int bpsk_pin_slice = pwm_gpio_to_slice_num(BPSK_PWM_PIN);
+  bpsk_pin_slice = pwm_gpio_to_slice_num(BPSK_PWM_PIN);
 /*
   // Setup PWM interrupt to fire when PWM cycle is complete
   pwm_clear_irq(bpsk_pin_slice);