Method and apparatus for attaching more than two disk devices to an IDE bus
View Patent ↗A method of connecting and operating three or more devices to an IDE bus under the conditions that: (1) no more than two IDE devices may be active at any given time on the same IDE bus, and (2) cable/trace lengths for the IDE bus may not exceed the limits set forth in the IDE bus standard. The IDE devices are configured for cable select connected to the IDE bus, wherein no more than two of the IDE devices are powered on at any given. Further, those IDE devices which are powered on at a give time, have the appropriate logic level asserted on CSEL line so that only one IDE device powered on at any time is a “Master” device, and only one IDE device powered on is a “Slave”.
1. A method for communicating data between a processor and one or more devices over an IDE bus, comprising the steps of:
connecting three or more devices to an IDE bus;
configuring each device as Cable Select; and
providing a device controller that selectively activates any two of the devices at the same time for data communication over the IDE bus.
2. The method of claim 1 , further comprising the steps of, the device controller:
identifying one or two of said three or more devices for data communication with the processor;
selecting a first of the identified devices as a master device;
if more than one device identified, then selecting the second of the identified devices as a slave device; and
activating each selected device, such that a maximum of only two devices among said three or more devices are active at the same time, whereby the activated devices can communicate with the processor over the IDE bus.
3. The method of claim 2 , further comprising the steps of, the device controller receiving identity of said devices for data communication from the processor.
4. The method of claim 1 , wherein the device controller is configured to activate two of said three or more devices connected to the IDE bus at a time, and to deactivate the remaining of said three or more devices.
5. The method of claim 4 , wherein the device controller is configured to activate said two devices by powering the two devices on, and to deactivate said remaining devices by powering said remaining devices off.
6. The method of claim 1 , wherein the device controller is configured to select each of said two devices via a selection signal for each of said two devices.
7. The method of claim 6 , wherein said selection signal comprises the IDE Cable Select line of each device.
8. The method of claim 1 , wherein at least one of the devices on the IDE bus comprises a disk drive.
9. A method for communicating data between a processor and three or more devices over an IDE bus, comprising the steps of:
(a) deactivating all the devices;
(b) identifying any one or any two of the devices for data communication with the processor;
(c) selecting a first of the identified devices as a master device;
(d) if more than one device identified, selecting the second of the identified devices as a slave device;
(e) activating each selected device, such that when any two devices are identified, then two devices are active at the same time; and
(f) communicating data between the processor and each activated device, over the IDE bus.
10. The method of claim 9 , further comprising the step of:
(g) deactivating all of the devices.
11. The method of claim 9 , further comprising the steps of repeating steps (a) through (f).
12. The method of claim 9 , further comprising the steps of, before step (a), connecting three or more IDE devices to the IDE bus.
13. The method of claim 9 , further comprising the steps of, before step (a), configuring each device as Cable Select.
14. The method of claim 13 , wherein:
step (c) further comprises the steps of selecting the first identified device as a master device via the Cable Select signal for that first device; and
step (d) further comprises the steps of selecting the second identified device as a slave device via the Cable Select signal for that second device.
15. The method of claim 9 , wherein:
in step (a) deactivating each device includes the steps of powering each device off; and
in step (e) activating each selected device includes the steps of powering each selected device on.
16. The method of claim 9 , wherein at least one of the devices on the IDE bus comprises a disk drive.
17. An Integrated Device Electronics (IDE) interface system for managing data communication between a processor and three or more devices connected to an IDE bus, the IDE interface system comprising:
a device controller for receiving device control signals to select any two of said devices for data communication with the processor;
wherein the device controller selectively activates any two of the devices at the same time for data communication with the processor over the IDE bus.
18. The IDE interface system of claim 17 , wherein the device controller is configured to: (a) identify any one or two of said three or more devices for data communication with the processor, and receive a signal from the processor to select one or two of the devices identified, (b) in response to the signal, select one of the identified devices as a master device; (c) if more than one device identified, then select the second of the identified devices as a slave device; and (d) activate each selected device, such that a maximum of only two devices among said three or more devices are active at the same time, whereby the activated devices can communicate with the processor over the IDE bus.
19. The IDE interface system of claim 17 , wherein the device controller is configured to activate two of said three or more devices connected to the IDE bus at the same time, and to deactivate the remaining of said three or more devices.
20. The IDE interface system of claim 19 , wherein the device controller is configured to activate said two devices by powering the two devices on, and to deactivate said remaining devices by powering said remaining devices off.
21. The IDE interface system of claim 17 , wherein the device controller is configured to select each of said two devices via a selection signal for each of said two devices.
22. The IDE interface system of claim 21 , wherein said selection signal comprises the IDE cable select line of each device.
23. The IDE interface system of claim 17 , further comprising an interface controller connected to said devices via the IDE bus, wherein the interface controller manages information flow between the processor and said devices over the IDE bus.
24. The IDE interface system of claim 17 , wherein at least one of the devices on the IDE bus comprises a disk drive.
25. A data storage system comprising:
three or more storage devices connected to an IDE bus for data communication with a processor over the IDE bus; and
a device controller connected to the devices, the device controller for receiving device control signals to select any two of said devices for data communication with the processor, wherein the device controller selectively activates any two of the devices at the same time for data communication with the processor over the IDE bus.
26. The data storage system of claim 25 , wherein the device controller is configured to: (a) identify any one or two of said three or more devices for data communication with the processor, and receive a signal from the processor to select one or two of the devices identified for data communication, (b) in response to the signal, select one of the identified devices as a master device; (c) if more than one device identified, then select the second of the identified devices as a slave device; and (d) activate each selected device, such that any two selected devices are active at the same time, whereby the activated devices can communicate with the processor over the IDE bus.
27. The data storage system of claim 25 , wherein the device controller is configured to activate any two of said three or more devices connected to the IDE bus at the same time, and to deactivate the remaining of said three or more devices.
28. The data storage system of claim 27 , wherein the device controller is configured to activate said two devices by powering the two devices on, and to deactivate said remaining devices by powering said remaining devices off.
29. The data storage system of claim 25 , wherein the device controller is configured to select each of said two devices via a selection signal for each of said two devices.
30. The data storage system of claim 29 , wherein said selection signal comprises the IDE cable select line of each device.
31. The data storage system of claim 25 , further comprising an interface controller connected to said devices via the IDE bus, wherein the interface controller manages information flow between the processor and said devices over the IDE bus.
32. The data storage system of claim 25 , wherein at least one of the devices on the IDE bus comprises a disk drive.
33. The data storage system of claim 25 further comprising:
a USB-to-IDE controller connected between the IDE bus and the processor, such that the storage devices are connected to the USB-to-IDE controller via the IDE bus;
wherein the device controller selectively activates the devices for data communication with the processor via the USB-to-IDE controller over the IDE bus.
34. The data storage system of claim 33 further comprising:
a USB controller connected to the processor, wherein the USB-to-IDE controller is connected between the IDE bus and the USB controller, such that the device controller selectively activates the devices for data communication with the processor via the USB controller and the USB-to-IDE controller over the IDE bus.