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//! Code shared across all i.MX RT 10xx chips.
use crate::ral;
pub(crate) fn prepare_pit(timer_delay_microseconds: u32) -> Option<crate::Pit> {
#[cfg(feature = "rtic")]
{
unsafe extern "C" {
// Not actually mut in cortex-m. But, no one is reading it...
static __INTERRUPTS: [core::cell::UnsafeCell<unsafe extern "C" fn()>; 240];
fn PIT();
}
unsafe {
__INTERRUPTS[crate::ral::interrupt::PIT as usize]
.get()
.write_volatile(PIT);
}
}
let ccm = unsafe { ral::ccm::CCM::instance() };
// Disable the PIT clock gate while we change the clock...
ral::modify_reg!(ral::ccm, ccm, CCGR1, CG6: 0b00);
// Set the periodic clock divider, selection.
// 24MHz crystal oscillator, divided by 24 == 1MHz PIT clock
ral::modify_reg!(
ral::ccm,
ccm,
CSCMR1,
PERCLK_PODF: DIVIDE_24,
PERCLK_CLK_SEL: PERCLK_CLK_SEL_1 // Oscillator clock
);
// Re-enable PIT clock
ral::modify_reg!(ral::ccm, ccm, CCGR1, CG6: 0b11);
let pit = unsafe { ral::pit::PIT::instance() };
Some(crate::Pit::new(&pit, timer_delay_microseconds))
}
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