at83c26 ATMEL Corporation, at83c26 Datasheet - Page 29

• Manufacturer Part Number: at83c26
• Description: Multiple Smart Card Reader Interface With Power Management
• Manufacturer: ATMEL Corporation

Transparent mode
Full transparent mode on SCn interfaces (n=1, 2)
7511D–SCR–02/07
During an emergency deactivation, the signals fall according to the order described in Fig18.
If the micro controller outputs ISO 7816 signals, a transparent mode allows to connect, CCLK,
CIO, CRST, CC4 and CC8 signals on outputs after an electrical level control. The AT83C26
level shifters adapt the card signals to the smart card voltage selection.
The CCLK micro controller signal can be connected to the A2/CK pins (see CKSn[2:0]).
CKSn[2:0] bits allow to select standard or transparent configuration for the CCLKn pin. A2/CK
inputs always give the TWI address at reset.
If A2/CK input is tied to the host micro controller and its reset value is unknown, a general call on
the TWI bus allows to reset all the AT83C26 devices and set its address after A2/CK input is
fixed.
Figure 18. Power Fail Detection
Figure 19. Emergency deactivation sequence
CCLK
CRST
CVCC
CIO,
CC4,
CC8
VPFDM
VPFDP
VCC
start standard deactivation
start emergency deactivation
AT83C26
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