27 lines
666 B
C
27 lines
666 B
C
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#include "../../cpu/isr.h"
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#include "../../tasking.h"
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#include "../../cpu/serial.h"
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#include <cpu/ports.h>
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void timer_handler(registers_t* r);
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void timer_init(int freq) {
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int div=1193180/freq;
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if (div>65535) {
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serial_printf("Frequency of %dHz too slow, min freq is 18 Hz\n");
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div=65535;
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freq=18;
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if (div==0) {
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serial_printf("Frequency of %dHz too slow, max freq is 1193180 Hz\n");
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div=1;
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freq=1193180;
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}
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} else {
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serial_printf("Setting PIT to %dHz using divisor of %d\n",freq,div);
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}
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isr_register_handler(0,timer_handler);
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port_byte_out(0x43,(div>>8)&0xFF);
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port_byte_out(0x40,div&0xFF);
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port_byte_out(0x40,0x2E);
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}
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