Extending secure digital input output capability on a controller bus
Embodiments of techniques for simultaneously connecting a plurality of expansion cards to a single bus of a host controller are described.
1. An apparatus comprising:
a plurality of secure digital input output (SDIO) device card slots, wherein an SDIO card slot comprises a slot capable of isolating interrupts when the associated card is deselected;
a bus of a host controller to simultaneously connect a plurality of expansion cards to a host device via the plurality of SDIO device card slots, wherein the plurality of expansion cards includes at least a secure digital (SD) memory card and a secure digital input output (SDIO) device;
a multiplex portion which is operable to select one of the plurality of expansion cards such that the host device may interact with the selected card via the host controller, wherein the multiplex portion:
includes one or more switches operable to select one of the multiplexed expansion cards; and
is configured to multiplex between the host controller and the plurality of expansion cards via a clock pin:
an interrupt isolation portion of the host controller configured to:
connect an interrupt signal associated with at least one expansion card via the bus when the expansion card is selected; and
isolate the interrupt signal from the bus when the at least one expansion card is deselected;
when the SD memory card is selected:
the interrupt signal of the SDIO device is routed via a general purpose input output (GPIO) pin of the host device, wherein the GPIO pin of the host device is isolated from the host controller; and
the interrupt isolation portion of the host controller associated with an SDIO device card slot employed to connect the SD memory card is deactivated; and
when the SDIO device is selected the interrupt signal is routed via a data pin of the host controller.
2. An apparatus as in claim 1 , wherein the secure digital input output (SDIO) devices are selected from the group consisting of a network interface, a wireless interface, a modem, global positioning satellite (GPS) device, a television tuner, speakers, a printer, a camera, a scanner, a voice recorder, and a projector.
3. An apparatus as in claim 1 , wherein:
the interrupt signal is to be communicated via a data pin of a corresponding said expansion card; and
the interrupt isolation portion includes one or more switches operable to:
route the interrupt signal from the data pin to a corresponding data pin of the host controller when the corresponding said expansion card is selected; and
route the interrupt signal from the data pin on a path isolated from the corresponding data pin of the host controller when the corresponding said expansion card is deselected.
4. An apparatus as described in claim 3 , wherein:
when the corresponding said expansion card is selected, the interrupt signal is to be monitored via the corresponding data pin of the host controller; and
when the corresponding said expansion card is deselected, the interrupt signal is to be monitored via the isolated path such that the occurrence of an interrupt when the corresponding said expansion card is deselected does not interfere with communication between the host controller and a selected said expansion card via the corresponding data pin of the host controller.
5. An apparatus as described in claim 1 , wherein the host controller is embedded in a microcontroller of the host device.
6. An apparatus as described in claim 1 , wherein the interrupt isolation portion is to route the interrupt signal of an expansion card such that the interrupt signal is to be monitored via the bus when the expansion card is selected and via a signal path distinct from the bus when the expansion card is deselected.
7. An apparatus as described in claim 1 , wherein the host controller is to connect a selected expansion card to a system bus of the host device to permit interaction of the host device with the selected card.
8. An apparatus as described in claim 1 , wherein the interrupt isolation portion is to selectably switch the interrupt signal between a data pin of the host controller when the card is selected and a general purpose input output pin (GPIO) of the host device when the card is deselected.
9. An apparatus as described in claim 1 , wherein:
the plurality of expansion cards includes at least two secure digital input output (SDIO) devices simultaneously connected to the host device via the bus; and
the interrupt signal of each SDIO device is routed via a data pin of the host controller when the corresponding SDIO device is selected and is isolated from the bus when the corresponding SDIO device is deselected.
10. An apparatus as described in claim 1 , wherein the interrupt signals are transmitted via a data pin of the at least one expansion card which correspond to a data pin of the host controller.