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** Copyright (C) 2019 Denis Shienkov <denis.shienkov@gmail.com>
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#include "core.h"
#include "regs.h"

enum cpu_freq_clk {
    CPU_CLK_12M = 0,
    CPU_CLK_24M,
    CPU_CLK_48M
};

#define cpu_freq_clk_get() \
    ((CPUCS & bmCLKSPD) >> 3)

#define cpu_freq_clk_set(freq_clk) \
    CPUCS = (CPUCS & ~bmCLKSPD) | (freq_clk << 3)

void core_init(void)
{
    // Set CPU clock to 48MHz.
    cpu_freq_clk_set(CPU_CLK_48M);
    sync_delay();
    // Set stretch to 0.
    CKCON = ((CKCON & (~bmSTRETCH)) | bmFW_STRETCH1);
    sync_delay();
    // Clear breakpoint register.
    BREAKPT = 0;
    sync_delay();
    // Set all 8051 interrupts to low priority
    IP = 0;
    sync_delay();
    // Clear interrupt enable bits.
    EIE = 0;
    sync_delay();
    // Clear all external interrupt flags.
    EXIF = 0;
    sync_delay();
}