srw%pws1@Sun.COM (Scott Wiesner) (01/11/89)
PS/2's with microchannel architectures use level triggered rather than edge triggered interrupts. The pic(s) much be programmed at initialization time for level triggered interrupts. The normal interrupt acknowledgment for a PC is not sufficient to lower the interrupt for a device. All the devices on a PS/2 have some operation that causes an interrupt to be cleared.. Most devices have their interrupt line lowered as a result of an operation that would normally be done at interrupt time anyway such as reading from the device. For the floppy drives, you must issue a sense interrupt status command to the controller. For the clock, you've got to set the high bit at io address 0x61. (Don't remember what this is. Some kind of misc. control register I think. I believe this is a read/modify/write operation.) I think these were the only two that required anything special. Hope this helps. I don't know much about minix, I just follow the group to see how much progress is being made. Scott