func main() {
setup.Performance(0)
periph.AHBClockEnable(periph.GPIOB)
periph.AHBReset(periph.GPIOB)
LED.SetMode(Blue, gpio.Out)
LED.SetMode(Green, gpio.Out)
vt := exce.NewTable(16)
vt[exce.NMI] = exce.VectorFor(defaultHandler)
vt[exce.HardFault] = exce.VectorFor(defaultHandler)
vt[exce.SysTick] = exce.VectorFor(sysTickHandler)
exce.UseTable(vt[:])
_, _, tenms := systick.Calib()
tenms *= 10 // stm32l1 returns value for 1 ms not for 10ms.
systick.SetReload(tenms * 100)
systick.SetFlags(systick.Enable | systick.TickInt)
// Sleep forever.
sleep.EnableSleepOnExit()
barrier.Sync() // not necessary on Cortex-M0,M3,M4
sleep.WFI()
// Execution should never reach there so the green LED
// should never light up.
LED.SetBit(Green)
}
func setSystick(sysclk int) {
if noos.MaxTasks() == 0 {
return
}
// Set tick period to 2 ms (500 context switches per second).
const period = 2
systick.SetReload(uint32(sysclk)*(1e6*period/1e3) - 1)
noos.SetTickPeriod(period)
}
func sysTickStart() {
// Defaults:
// One context switch per 1e6 SysTicks (70/s for 70 Mhz, 168/s for 168 MHz)
systick.SetReload(1e6 - 1)
systick.WriteFlags(systick.Enable | systick.TickInt | systick.ClkCPU)
}