48 lines
1.2 KiB
C
48 lines
1.2 KiB
C
#ifndef VasEBoot_SPEAKER_HEADER
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#define VasEBoot_SPEAKER_HEADER 1
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#include <VasEBoot/cpu/io.h>
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#include <VasEBoot/i386/pit.h>
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/* The frequency of the PIT clock. */
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#define VasEBoot_SPEAKER_PIT_FREQUENCY 0x1234dd
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static inline void
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VasEBoot_speaker_beep_off (void)
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{
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unsigned char status;
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status = VasEBoot_inb (VasEBoot_PIT_SPEAKER_PORT);
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VasEBoot_outb (status & ~(VasEBoot_PIT_SPK_TMR2 | VasEBoot_PIT_SPK_DATA),
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VasEBoot_PIT_SPEAKER_PORT);
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}
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static inline void
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VasEBoot_speaker_beep_on (VasEBoot_uint16_t pitch)
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{
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unsigned char status;
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unsigned int counter;
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if (pitch < 20)
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pitch = 20;
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else if (pitch > 20000)
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pitch = 20000;
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counter = VasEBoot_SPEAKER_PIT_FREQUENCY / pitch;
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/* Program timer 2. */
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VasEBoot_outb (VasEBoot_PIT_CTRL_SELECT_2
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| VasEBoot_PIT_CTRL_READLOAD_WORD
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| VasEBoot_PIT_CTRL_SQUAREWAVE_GEN
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| VasEBoot_PIT_CTRL_COUNT_BINARY, VasEBoot_PIT_CTRL);
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VasEBoot_outb (counter & 0xff, VasEBoot_PIT_COUNTER_2); /* LSB */
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VasEBoot_outb ((counter >> 8) & 0xff, VasEBoot_PIT_COUNTER_2); /* MSB */
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/* Start speaker. */
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status = VasEBoot_inb (VasEBoot_PIT_SPEAKER_PORT);
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VasEBoot_outb (status | VasEBoot_PIT_SPK_TMR2 | VasEBoot_PIT_SPK_DATA,
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VasEBoot_PIT_SPEAKER_PORT);
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}
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#endif
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