Method and system for hot docking a portable computer to a docking station via the primary PCI bus

• US 5,933,609 A
• Filed: 04/08/1996
• Issued: 08/03/1999
• Est. Priority Date: 04/08/1996
• Status: Expired due to Fees

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: VLSI Technology, Inc. (Koninklijke Philips N.V.)
• Inventors: Crews, Michael, Chambers, Peter, Evoy, David, Story, Franklyn H., Walker, Gary
• Primary Examiner(s): Sheikh, Ayaz R.
• Assistant Examiner(s): Thlang, Eric S.
• Application Number:
  US08/629,015
• Time in Patent Office: 1,212 Days
• Field of Search: 395/281, 395/800, 395/671, 395/750, 395/294, 327/293, 361/686, 361/683, 364/514 R
• US Class Current: 710/304
• CPC Class Codes: G06F 1/1632 External expansion units, e.g. docking stations
• CPC Class Codes: G06F 13/4081 Live connection to bus, e.g. hot-plugging current or voltage limitation during live insertion H02H9/004

Abstract

A portable computer and corresponding docking station, where the portable computer may be inserted into or removed from the docking station without concern relating to the state of either the portable computer or of the docking station. The hot docking sequence is performed by establishing a direct connection to the primary PCI bus without the risk of any possible system damage, file damage, or data loss. This can be accomplished even while the portable computer system is powered on and is actively running. The present invention prevents glitches from occurring in pre-existing pins and adds four new pins to implement this novel hot docking sequence. Furthermore, hot undocking can be readily performed as well by basically reversing the docking sequence.

Claims

1. An apparatus for hot docking a portable computer with a docking station through a primary PCI bus, comprising:

a docking sequencer coupled to the primary PCI bus for detecting a docking condition and preparing the portable computer and docking station for mating of docking signal pins;

a PCI to PCI bridge for exchanging signals between the primary PCI bus of the docking station and a secondary PCI bus of the portable computer;

a connector for detachably coupling the PCI to PCI bridge to the primary PCI bus;

a controller coupled to the primary PCI bus for generating reset and clock signals to the PCI to PCI bridge, wherein signals including address, C/BE, DEVSEL, FRAME, REQ, IDSEL, IRDY, PAR, PERR, SERR, STOP, LOCK, TRDY, and an IRQSER (serialized interrupt request) signal are tri-stated during the mating of the docking signal pins, and wherein the clock signal from the controller to the PCI to PCI bridge is tri-stated during a docking sequence; and

a handler coupled to the controller for configuring the PCI to PCI bridge, identifying devices coupled to the PCI to PCI bridge, and notifying an operating system of additional resources when the portable computer is docked.

2. The apparatus of claim 1, wherein the docking signal pins are comprised of:

a first pin for indicating that the portable computer is about to dock;

a second pin to indicate that the portable computer is about to undock;

a third pin that provides the PCI to PCI bridge with a primary PCI clock, wherein the clock can be tri-stated, enable and stopped, or enabled and active;

a fourth pin for providing a reset signal which can be tri-stated, driven low, or driven high.

3. The apparatus of claim 2, wherein when the second pin indicates that the portable computer is to be undocked, the handler notifies the operating system to close resources associated with the docking station and the controller stops a PCI clock, three-states PCI signals, and three-states a reset signal and a clock signal to the PCI to PCI bridge.

4. The apparatus of claim 1 further comprising an arbiter coupled to the primary PCI bus, wherein the arbiter generates a grant signal to grant ownership of the primary PCI bus and does not remove the grant signal until a requesting device signals the start of a transaction on the primary PCI bus, in order to insure that the controller maintains the primary PCI bus ownership until final contact between the docking connector and the docking receiver is established.

5. The apparatus of claim 1, wherein the reset signal is pulled down to reset the PCI to PCI bridge which causes PCI signals associated with the PCI to PCI bridge to become tri-stated.

6. The apparatus of claim 1 further comprising a pull-down resistor to keep a clock run signal asserted during a docking sequence.

7. The apparatus of claim 1 further comprising a docking data frame to switch a serial bus to a continuous mode of operation in order to tri-state the IRQSER signal.

8. The apparatus of claim 1 further comprising a pull-up resistor coupled to the SERR pin on the primary PCI interface of the PCI to PCI bridge and the bridge, which converts the SERR signal on a secondary PCI bus to a serial bus data frame.

9. In a computer system having a portable computer that is dockable with a docking station, a method for hot docking the portable computer with the docking station through a primary PCI bus, comprising the steps of:

detecting a docking condition and preparing the portable computer and docking station for mating of docking signal pins;

exchanging signals between the primary PCI bus of the docking station and a secondary PCI bus of the portable computer;

generating reset and clock signals from a controller to the PCI to PCI bridge, wherein signals including address, C/BE, DEVSEL, FRAME, REQ, IDSEL, IRDY, PAR, PERR, SERR, STOP, LOCK, and TRDY are tri-stated during the mating of the docking signal pins;

asserting the reset signal to reset the PCI to PCI bridge, wherein the reset PCI to PCI bridge causes PCI signals associated with the PCI to PCI bridge to become tri-stated;

tri-stating the clock signal from the controller to the PCI to PCI bridge during a docking sequence; and

configuring the PCI to PCI bridge, identifying devices coupled to the PCI to PCI bridge, and notifying an operating system of additional resources when the portable computer is docked.

10. The method of claim 9 further comprising the steps of:

indicating through a first pin that the portable computer is about to dock;

indicating through a second pin that the portable computer is about to undock;

providing the PCI to PCI bridge with a primary PCI clock through a third pin, wherein the clock can be three-stated, enable and stopped, or enabled and active;

providing a reset signal through a fourth pin, wherein the reset signal can be three-stated, driven low, or driven high.

11. The method of claim 10, wherein when the second pin indicates that the portable computer is to be undocked, the operating system closes resources associated with the docking station and the controller stops a PCI clock, three-states PCI signals, and three states a reset signal and a clock signal to the PCI to PCI bridge.

12. The method of claim 9 further comprising the step of tri-stating an IRQSER (serialized interrupt request) signal during the mating of docking signal pins.

13. The method of claim 12 further comprising the step of asserting a clock run signal when the portable computer is docked.

14. The method of claim 12 further comprising the step of generating a docking data frame to switch a serial bus to a continuous mode of operation in order to tri-state the IRQSER signal.

15. The method of claim 14, wherein the step of notifying a system management module handler that the system resources have changed, is further comprised of:

notifying a system management module handler by generating a system management interrupt signal;

configuring the PCI to PCI bridge, and;

enumerating the devices behind the PCI to PCI bridge.

16. The method of claim 12 further comprising the step of converting the SERR signal on a secondary PCI bus to a serial bus data frame.

17. The method of claim 9 further comprising the step of an arbiter generating a grant signal to grant ownership of the primary PCI bus, wherein the grant signal is not removed until a requesting device indicates the start of a transaction on the primary PCI bus, in order to insure that the controller maintains the primary PCI bus ownership until final contact between the docking connector and the docking receiver is established.

18. In a computer system having a docking station and a portable computer, a method for unmating a docking connector on the portable computer and a docking receiver on the docking station comprising the steps of:

asserting an undock signal to indicate that the portable computer is preparing to undock, wherein said undock signal is the result of a user request to the portable computer'"'"'s operating system that the portable computer be undocked, or ejected, from the docking station;

closing all open files and resources in the docking computer;

turning off power to any devices on a secondary bus;

stopping a primary PCI clock in the portable computer, stopping a PCI to PCI bridge secondary clock in the docking station, and tri-stating outputs including the signals C/BE, DEVSEL, FRAME, REQ, IDSEL, IRDY, PAR, PERR, SERR, STOP, LOCK, TRDY, and IRQSER (serialized interrupt request);

turning power off to the docking station, and;

detecting when the docking connector and the docking receiver have cleanly detached.