ST7PSCR1E4M1/XXX View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
ST7PSCR1E4M1/XXX
STMicroelectronics
ST7PSCR1E4M1/XXX Datasheet PDF : 102 Pages
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ST7SCR
SMARTCARD INTERFACE (Cont’d)
12.4.3.5 Card detection mechanism
The CRDDET bit in the CRDCR Register indicates
if the card presence detector (card switch) is open
or closed when a card is inserted. When the
CRDIRF bit of the CRDSR is set, it indicates that a
card is present.
To be able to power-on the smartcard, card pres-
ence is mandatory. Removing the smartcard will
automatically start the ISO7816-3 card deactiva-
tion sequence (see Section 12.4.3.6).
There is no hardware debouncing: The CRDIRF
bit changes whenever the level on the CRDDET
pin changes. The card switch can generate an in-
terrupt which can be used to wake up the device
from suspend mode and for software debouncing.
Three different cases can occur:
– The microcontroller is in run mode, waiting for
card insertion:
Card insertion generates an interrupt and the
Figure 32. Card detection block diagram
CRDIRF bit in the CRDSR register is set. De-
bouncing is managed by software. After the time
required for debouncing, if the CRDIRF bit is set,
the CRDVCC bit in the CRDCR register is set by
software to apply the selected voltage to the
CRDVCC pin
– The microcontroller is in suspend mode and a
card is inserted:
The ST7 is woken up by the interrupt. The card
insertion is then handled in the same way as in
the previous case.
– The card is removed:
– The CRDIRF bit is reset without hardware de-
bouncing
– A Card Insertion/Removal interrupt is generat-
ed, (if enabled by the CRDIRM bit in the
MISCR2 register)
– The CRDVCC bit is immediately reset by
hardware, starting the card deactivation se-
quence.
SMARTCARD INTERFACE (CRD)
EDGE DETECTOR
CARD INSERTION/REMOVAL
Interrupt Request
7
CRD
IRF
CRDSR
7
CRD
IRM
MISCR2
1
0
7
DET
CNF
CRDCR
0
Pull-up
0
CRDDET
0
59/102
1
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