ST7PSCR1E4M1/XXX View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST7PSCR1E4M1/XXX

8-BIT LOW-POWER, FULL-SPEED USB MCU WITH 16K FLASH, 768 RAM, SMARTCARD I/F, TIMER

STMicroelectronics 

ST7SCR

SMARTCARD INTERFACE (Cont’d)

12.4.3.6 Card Deactivation Sequence

This sequence can be activated in two different

ways:

– Automatically as soon as the card presence de-

tector detects a card removal (via the CRDIRF bit

in the CRDSR register, refer to Section 12.4.3.5).

– By software, writing the CRDVCC bit in the CRD-

CR register, for example:

– If there is a smartcard current overflow (i.e.

when the IOVFF bit in the CRDSR register is

set)

– If the voltage is not within the specified range

(i.e. when the VCARDOK bit in the CRDSR

register is cleared), but software must clear

the CRDVCC bit in the CRDCCR register to

start the deactivation sequence.

When the CRDVCC bit is cleared, this starts the

deactivation sequence. CRDCLK, CRDIO,

CRDC4 and CRDC8 pins are then deactivated as

shown in Figure 33:

Figure 33. Card deactivation sequence

8 CPU Clk cycles

CRDVCC pin

CRDRST pin

CRDCLK pin

CRDIO pin

CRDC4 pin

CRDC8 pin

Figure 34. Card voltage selection and power OFF block diagram

5V

SMARTCARD

POWER SUPPLY

BLOCK

CRDVCC

Card voltage selection

2

7

CRD

IRF

CRDSR

IOVF

VCARD

OK

7

CRDIER

IOVM VCRD

M

2

2

0

7

CRDCR

VCARDVCARD

1

0

0

7

CRDCCR

0

0

CRD

VCC

7

CRDIPR

IOVP VCRD

P

0

VCARDOK Interrupt Request

IOVF Interrupt Request

POWER OFF

BLOCK

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