46 lines
979 B
C
46 lines
979 B
C
#include "uart.h"
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#include "port.h"
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static int uart;
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enum {
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COM1 = 0x3f8,
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};
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void uartinit() {
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// Turn off the FIFO
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port_byte_out(COM1+2, 0);
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// 9600 baud, 8 data bits, 1 stop bit, parity off.
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port_byte_out(COM1+3, 0x80); // Unlock divisor
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port_byte_out(COM1+0, 115200/9600);
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port_byte_out(COM1+1, 0);
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port_byte_out(COM1+3, 0x03); // Lock divisor, 8 data bits.
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port_byte_out(COM1+4, 0);
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port_byte_out(COM1+1, 0x01); // Enable receive interrupts.
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// If status is 0xFF, no serial port.
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if(port_byte_in(COM1+5) == 0xFF)
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return;
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uart = 1;
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// Acknowledge pre-existing interrupt conditions;
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// enable interrupts.
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port_byte_in(COM1+2);
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port_byte_in(COM1+0);
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}
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void
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uartputc(char c)
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{
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int i;
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if (!uart)
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return;
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/* What is that *skeleton emoji*? */
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for (i = 0; i < 128 && !(port_byte_in(COM1+5) & 0x20); i++) {
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asm("pause");
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}
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port_byte_out(COM1+0, c);
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}
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