Texas Instruments PCI7621 PC Card Insertion/Removal and Recognition, UltraMedia Card Detection

3.5.1PC Card Insertion/Removal and Recognition

The PC Card Standard (release 8.1) addresses the card-detection and recognition process through an interrogation procedure that the socket must initiate on card insertion into a cold, nonpowered socket. Through this interrogation, card voltage requirements and interface (16-bit versus CardBus) are determined.

The scheme uses the card-detect and voltage-sense signals. The configuration of these four terminals identifies the card type and voltage requirements of the PC Card interface.

3.5.2Low Voltage CardBus Card Detection

The card detection logic of the PCI7x21/PCI7x11 controller includes the detection of Cardbus cards with VCC = 3.3 V and VPP = 1.8 V. The reporting of the 1.8-V CardBus card (VCC = 3.3 V, VPP = 1.8 V) is reported through the socket present state register as follows based on bit 10 (12V_SW_SEL) in the general control register (PCI offset 86h, see Section 4.31):

•If the 12V_SW_SEL bit is 0 (TPS2228 is used), then the 1.8-V CardBus card causes the 3VCARD bit in the socket present state register to be set.

•If the 12V_SW_SEL bit is 1 (TPS2226 is used), then the 1.8-V CardBus card causes the XVCARD bit in the socket present state register to be set.

3.5.3UltraMedia Card Detection

The PCI7x21/PCI7x11 controller is capable of detecting all the UltraMedia devices defined by the PCMCIA Proposal 0262 – MultiMedia Cards, Secure Digital, Memory Stick devices, and Smart Card devices. The detection of these devices is made possible through circuitry included in the PCI7x21/PCI7x11 controller and the adapters used to interface these devices with the PC Card/CardBus sockets. No additional hardware requirements are placed on the system designer in order to support these devices.

The PC Card Standard addresses the card detection and recognition process through an interrogation procedure that the socket must initiate upon card insertion into a cold, unpowered socket. Through this interrogation, card voltage requirements and interface type (16-bit vs. CardBus) are determined. The scheme uses the CD1, CD2, VS1, and VS2 signals (CCD1, CCD2, CVS1, CVS2 for CardBus). A PC Card designer connects these four terminals in a certain configuration to indicate the type of card and its supply voltage requirements. The encoding scheme for this, defined in the PC Card Standard, is shown in Table 3−2.

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