RTC interruption

[pedrodemargomes]

I am trying to set rtc interruptions, but it is not working(triple fault).
I have already setted PIC1 and PIC2 and their interruption masks.

This is the code that sets the rtc interruptions:

Code: Select all

/*          Ports
*        PIC1   PIC2
*Command 0x20   0xA0
*Data    0x21   0xA1
*/


asm volatile ( "cli" ); 
 
uint8_t rate = 0x05;
outb(0x70, 0x8B);
char prev = inb(0x71);
outb(0x70, 0x8B);
outb(0x71, prev | 0x40);

outb(0x70, 0x8A);
prev = inb(0x71);
outb(0x70, 0x8A);
outb(0x71, (prev & 0xF0) | rate );
outb(0x70, 0x0C);
inb(0x71);
 
// PIC 2
/* 0xFE is 11111110 - enables IRQ0 (rtc)*/
uint8_t prevIrq = inb(0xA1);
outb(0xA1 , 0xFE & prevIrq );
     
// PIC 1
/* 0xFB is 11111011 - enables IRQ2 (rtc)*/
prevIrq = inb(0x21);    
outb(0x21 , 0xFB & prevIrq );     

asm volatile ( "sti" ); 

This is the rtc interruption handler:

Code: Select all

/*          Ports
*        PIC1   PIC2
*Command 0x20   0xA0
*Data    0x21   0xA1
*/

outb(0xA1, 0x20);
outb(0x20, 0x20);
/* 
do something
*/ 

[iansjack]

No "RTI" instruction?

[Octocontrabass]

I am trying to set rtc interruptions, but it is not working(triple fault).

Have you figured out where in your code the triple fault occurs?

Code: Select all

outb(0xA1, 0x20);

I don't think this line of code does what you want.

[pedrodemargomes]

I am trying to set rtc interruptions, but it is not working(triple fault).

Have you figured out where in your code the triple fault occurs?

Yes, it occurs at the first rtc interruption.

Code: Select all

outb(0xA1, 0x20);

I don't think this line of code does what you want.

It supossed to be 0xA0, i fixed that .
But the problem is that the program does not get there, it fails before that.

I will let my git repository here:
https://gitlab.com/pedrodemargomes/BootTeste_OS

[Brendan]

Hi,

I am trying to set rtc interruptions, but it is not working(triple fault).

In that case it's probably a problem with your GDT, IDT or stack (and not a problem with any of the code you posted). You should be able to get some information about what caused the triple fault from an emulator's logs (e.g. if the first exception was a general protection fault or page fault, etc).

I will let my git repository here:
https://gitlab.com/pedrodemargomes/BootTeste_OS

I couldn't find any source code there.


Cheers,

Brendan

[pedrodemargomes]

Hi,

I am trying to set rtc interruptions, but it is not working(triple fault).

In that case it's probably a problem with your GDT, IDT or stack (and not a problem with any of the code you posted). You should be able to get some information about what caused the triple fault from an emulator's logs (e.g. if the first exception was a general protection fault or page fault, etc).

I will let my git repository here:
https://gitlab.com/pedrodemargomes/BootTeste_OS

I couldn't find any source code there.


Cheers,

Brendan

Sorry, i forgot to change the permissions , now it is right.
I could not find any usefull information in the log files about the the faults .

[MichaelPetch]

Where in your code do you set up the IDT entry for your RTC Interrupt handler? I see you set up an entry for the keyboard at IDT[0x21] to handle IRQ1. To handle IRQ8 (RTC) you would need an IDT entry at IDT[0x28] with the way you set up the PICs and then point it at your rtc_handler function.