46 lines
1.3 KiB
C
46 lines
1.3 KiB
C
/*
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* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include "pico.h"
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// For MHZ definitions etc
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#include "hardware/clocks.h"
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#include "hardware/platform_defs.h"
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#include "hardware/regs/xosc.h"
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#include "hardware/structs/xosc.h"
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void xosc_init(void) {
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// Assumes 1-15 MHz input
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assert(XOSC_MHZ <= 15);
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xosc_hw->ctrl = XOSC_CTRL_FREQ_RANGE_VALUE_1_15MHZ;
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// Set xosc startup delay
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uint32_t startup_delay = (((12 * MHZ) / 1000) + 128) / 256;
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xosc_hw->startup = startup_delay;
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// Set the enable bit now that we have set freq range and startup delay
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hw_set_bits(&xosc_hw->ctrl, XOSC_CTRL_ENABLE_VALUE_ENABLE << XOSC_CTRL_ENABLE_LSB);
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// Wait for XOSC to be stable
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while(!(xosc_hw->status & XOSC_STATUS_STABLE_BITS));
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}
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void xosc_disable(void) {
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uint32_t tmp = xosc_hw->ctrl;
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tmp &= (~XOSC_CTRL_ENABLE_BITS);
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tmp |= (XOSC_CTRL_ENABLE_VALUE_DISABLE << XOSC_CTRL_ENABLE_LSB);
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xosc_hw->ctrl = tmp;
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// Wait for stable to go away
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while(xosc_hw->status & XOSC_STATUS_STABLE_BITS);
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}
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void xosc_dormant(void) {
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// WARNING: This stops the xosc until woken up by an irq
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xosc_hw->dormant = XOSC_DORMANT_VALUE_DORMANT;
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// Wait for it to become stable once woken up
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while(!(xosc_hw->status & XOSC_STATUS_STABLE_BITS));
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} |