OSDev.org

hi ppl. about the floppy disk controller, i'm using an intel 82077 all-in-one chip;
so i went to check the wiki along the datasheet:
https://wiki.osdev.org/Floppy_Disk_Controller
then i saw the note,
"Note2: some tutorials seem to claim that changing/setting the datarate causes an IRQ6. This is false."

However, the 82077 datasheet page 41, shows a diagram with a procedure to init the controller that includes "Program Datarate via CCR" then "Wait for interrupt" then "Issue Sense Interrupt Status".

it seems that the fdc is not making an IRQ after setting CCR, (for now my program just aborts the wait with a timeout).
i'm still wondering why is stated in the datasheet that one should get an irq.
http://www.buchty.net/casio/files/82077.pdf

The datasheet shows the order in which you should initialize the controller, not cause and effect. The interrupt is caused by resetting the controller. It takes a while after reset for the controller to raise an interrupt request, so you have enough time to write CCR while you wait for the interrupt.