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DEVELOPING A USB SMARTCARD READER WITH ST7SCR

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unsigned char CRD_GetConvention(void)

This function returns the convention currently in use in the CRD. There are two conventions:

– CRD_DirectConv

– CRD_InverseConv

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unsigned char CRD_GetClockStatus(void)

This function returns the status of the CRD clock signal. There are three possible states for the

clock signal:

– CRD_ClockRunning

– CRD_ClockStoppedLow

– CRD_ClockStoppedHigh

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unsigned char CRD_SetClock(unsigned char ClockState)

This function modifies the state of the CRD clock signal. ClockState can be one of the fol-

lowing ones:

– CRD_ClockRunning

– CRD_ClockStoppedLow

– CRD_ClockStoppedHigh

– CRD_ClockStoppedLowOrHigh

This function returns one of the following error codes:

– Slot_No_Error

– SlotError_ICC_Mute

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unsigned char CRD_SetEtu(unsigned int Etu, unsigned char Comp)

This function sets the Elementary Time Unit registers to the value of the Etu variable. The

value of this variable must be a positive integer between 12 and 2048. If the Etu value is 2048,

the hardware registers are cleared and the CRD behaves as if it was set to 2048. The Comp

value can be 0 or 1. It is written to the COMP bit of register CRDETU1. For more information,

please refer to the ST7SCR datasheet.

This function will return 0 if the CRDETU registers are correct and 0xFF if the input values are

incorrect.

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void CRD_SetGuardTime(unsigned int GuardTime)

void CRD_SetWaitingTime(unsigned long WaitingTime)

These functions enter positive integer values in the hardware timer registers.