pbio/drv/clock/clock_ev3: Track whether timer is suspended

Author: ArcaneNibble

lib/pbio/drv/clock/clock_ev3.c

@@ -36,6 +36,11 @@ const uint32_t timer_ms_period = (auxclk_freq_hz / 1000) - 1;
  */
 volatile uint32_t systick_ms = 0;
 
+/**
+ * Whether the timer has been suspended
+ */
+static int systick_is_suspended;
+
 /**
  * The systick interrupt service routine (ISR) which will be called every millisecond.
  */
@@ -57,6 +62,7 @@ void systick_isr_C(void) {
 void systick_suspend(void) {
     /* Disable the timer interrupt */
     TimerDisable(SOC_TMR_0_REGS, TMR_TIMER12);
+    systick_is_suspended = 1;
 }
 
 /**
@@ -65,6 +71,7 @@ void systick_suspend(void) {
 void systick_resume(void) {
     /* Enable the timer interrupt */
     TimerEnable(SOC_TMR_0_REGS, TMR_TIMER12, TMR_ENABLE_CONT);
+    systick_is_suspended = 0;
 }
 
 /**
@@ -116,8 +123,8 @@ void pbdrv_clock_busy_delay_ms(uint32_t ms) {
 }
 
 bool pbdrv_clock_is_ticking(void) {
-    // TODO
-    return true;
+    // TODO: Check current interrupt status as well
+    return !systick_is_suspended;
 }
 
 #endif // PBDRV_CONFIG_CLOCK_TIAM1808