27 lines
663 B
Python
27 lines
663 B
Python
import asm
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import t, c
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PIT_CHANNEL0: t.CDefine = 0x40
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PIT_CHANNEL1: t.CDefine = 0x41
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PIT_CHANNEL2: t.CDefine = 0x42
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PIT_COMMAND: t.CDefine = 0x43
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def pit_init(frequency: t.CInt):
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# 参数验证：确保频率为正数
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if frequency <= 0: return
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# 计算除数，使用16位无符号整数
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divisor: t.CUInt32T = 1193180 / frequency
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# 发送命令字：通道0，先低后高，模式3（方波），二进制计数
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asm.outb(PIT_COMMAND, 0x36)
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asm.io_wait()
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# 写入低字节
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asm.outb(PIT_CHANNEL0, divisor & 0xFF)
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asm.io_wait()
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# 写入高字节
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asm.outb(PIT_CHANNEL0, (divisor >> 8) & 0xFF)
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asm.io_wait()
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