42 строки
1 002 Б
Go
42 строки
1 002 Б
Go
//go:build rp2040
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package machine
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import (
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"device/rp"
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"runtime/volatile"
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"unsafe"
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)
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type xoscType struct {
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ctrl volatile.Register32
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status volatile.Register32
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dormant volatile.Register32
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startup volatile.Register32
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reserved [3]volatile.Register32
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count volatile.Register32
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}
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var xosc = (*xoscType)(unsafe.Pointer(rp.XOSC))
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// init initializes the crystal oscillator system.
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//
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// This function will block until the crystal oscillator has stabilised.
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func (osc *xoscType) init() {
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// Assumes 1-15 MHz input
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if xoscFreq > 15 {
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panic("xosc frequency cannot be greater than 15MHz")
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}
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osc.ctrl.Set(rp.XOSC_CTRL_FREQ_RANGE_1_15MHZ)
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// Set xosc startup delay
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delay := (((xoscFreq * MHz) / 1000) + 128) / 256
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osc.startup.Set(uint32(delay))
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// Set the enable bit now that we have set freq range and startup delay
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osc.ctrl.SetBits(rp.XOSC_CTRL_ENABLE_ENABLE << rp.XOSC_CTRL_ENABLE_Pos)
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// Wait for xosc to be stable
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for !osc.status.HasBits(rp.XOSC_STATUS_STABLE) {
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}
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}
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