Dual interface card with backward and forward compatibility
View Patent ↗Techniques are presented that allow a memory card operable according to two protocols (such as a legacy protocol and newer protocol), and having a corresponding dual interface, to be used with hosts that support the new protocol as well as having backward compatibility with legacy hosts, while preventing the use of legacy cards with hosts that support the new protocol but do not support the legacy protocol. The card that supports the new protocol has a similar form factor to the legacy card, includes an indentation. A host that supports the new, but not the legacy, type card includes a mechanical structure within the attachment slot that, based on the card indentation, can distinguish the card types and prevent the non-supported card from being attached.
1. A non-volatile memory card operable according to a first protocol and according to a second protocol and removably connectable to a host through a slot in the host, the memory card comprising:
a first set of contacts for connecting the memory card to a host with which the memory card can communicate using the first protocol;
a second set of contacts for connecting the memory card the host with which the memory card can communicate using the second protocol, wherein the first and second sets of contacts differ by at least one of the contacts; and
first and second edges of the memory card, the first edge having an indentation configured to be mechanically engaged by an edge indentation detector in the host,
wherein the indentation in the first edge of the memory card is adapted to identify the memory card to the host as operable in accordance with the first protocol, while the memory card is inserted into the slot with the second edge being introduced thereto, so as to enable the host to distinguish between such memory card and a second memory card with a similar form factor except for the indentation and that is not operable according to the first protocol.
2. The non-volatile memory card as in claim 1 , wherein the first edge is orthogonal to the second edge.
3. The non-volatile memory card as in claim 1 , wherein the slot is rectangular or of other form that fits the physical shape of the memory card.
4. The non-volatile memory card of claim 1 , wherein the form factor of the memory card allows for connection to a host that only supports the second protocol through use of the second set of contacts.
5. The non-volatile memory card of claim 1 , where the first and second sets of contacts are distinct.
6. The non-volatile memory card of claim 1 , where the first and second sets of contacts share one or more contacts.
7. The non-volatile memory card of claim 1 , where one of the first and second sets of contacts is a subset of the other of the first and second sets of contacts.
8. The non-volatile memory card of claim 1 , wherein the host is operable to communicate with the memory card using only the first of the first and second protocols.
9. The non-volatile memory card of claim 1 , where the second type has the second set of contacts, but not those of the first set that are not also in the second set.
10. The non-volatile memory card of claim 1 , wherein the second edge of the memory card is inserted into a first host slot for connection to a host for operation according to the first protocol and an edge of the memory card other than the second edge is inserted into a second host slot for connection to a host for operation according to the second protocol.
11. The non-volatile memory card of claim 1 , wherein the form factor is one of a secure digital card and a micro secure digital card.
12. The non-volatile memory card of claim 1 , wherein the second protocol is a micro secure digital card protocol.
13. The non-volatile memory card of claim 1 , wherein the first protocol is an updated version of the second protocol.
14. The non-volatile memory card of claim 1 , wherein the indentation is configured to accept a pivoting lever arm located within the slot of the host.
15. The non-volatile memory card of claim 1 , wherein the edge indentation detector enables the memory card to be fully inserted into the slot.
16. The non-volatile memory card of claim 1 , wherein the first and the second edges define an angle therebetween.