Computer Hardware User Manual

Intel® 460GX Chipset Software Developer’s Manual 3-7
System Architecture
3.8.1 Slot Power-up and Enable
To power-up a PCI slot, software sets a command bit in a register. Then the hot-plug logic performs
the following steps:
1. Set PWREN active to the slot and clock the parallel latch.
2. Set CLKEN# active to the slot but do not clock the parallel latch.
3. Wait 200 msec for slot power to stabilize, except in test mode.
4. Gain ownership of the PCI bus through arbitration.
5. Clock the parallel latch.
6. Release ownership of the bus after 480 nsec.
7. Set RESET# inactive to the slot but do not clock the parallel latch.
8. Wait 200 msec for slot clock to stabilize, except in test mode.
9. Gain ownership of the PCI bus through arbitration.
10. Clock the parallel latch.
11. Release ownership of the bus after 480 nsec.
12. Set BUSEN# active to the slot but do not clock the parallel latch.
13. Wait 1000 msec for PCI card initialization, except in test mode.
14. Gain ownership of the PCI bus through arbitration.
15. Clock the parallel latch.
16. Release ownership of the bus after 480 nsec.
3.8.2 Slot Power-down and Disable
To power-down a PCI slot, software sets a command bit in a register. Then the hot-plug logic
performs the following steps:
1. Set BUSEN# inactive to the slot but do not clock the parallel latch.
2. Gain ownership of the PCI bus through arbitration.
3. Clock the parallel latch.
4. Release ownership of the bus after 480 nsec.
5. Set RESET# active to the slot but do not clock the parallel latch.
6. Gain ownership of the PCI bus through arbitration.
7. Clock the parallel latch.
8. Release ownership of the bus after 480 nsec.
9. Set CLKEN# inactive to the slot but do not clock the parallel latch.
10. Gain ownership of the PCI bus through arbitration.
11. Clock the parallel latch.
12. Release ownership of the bus after 480 nsec.
13. Set PWREN inactive to the slot and clock the parallel latch.