Serial Ports: Difference between revisions
Add code to test serial chip before even thinking of sending bytes
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(Add code to test serial chip before even thinking of sending bytes) |
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Line 207:
===Initialization===
<source lang="C">
#define PORT 0x3f8
outb(PORT + 1, 0x00); // Disable all interrupts
outb(PORT + 3, 0x80); // Enable DLAB (set baud rate divisor)
Line 217:
outb(PORT + 2, 0xC7); // Enable FIFO, clear them, with 14-byte threshold
outb(PORT + 4, 0x0B); // IRQs enabled, RTS/DSR set
outb(PORT + 4, 0x1E); // Set in loopback mode, test the serial chip
outb(PORT + 0, 0xAE); // Test serial chip (send byte 0xAE and check if serial returns same byte)
// Check if serial is faulty (i.e: not same byte as sent)
if(inb(PORT + 0) != 0xAE) {
return 1;
}
// If serial is not faulty set it in normal operation mode
// (not-loopback with IRQs enabled and OUT#1 and OUT#2 bits enabled)
outb(PORT + 4, 0x0F);
return 0;
}
</source>
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