at83c26 ATMEL Corporation, at83c26 Datasheet - Page 32

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

Slew rate control
Power down mode
32
Bit name
CARDIN1
CARDIN2
VCARD_OK1
VCARD_OK2
VCARD_OK3
VCARD_OK4
VCARD_OK5
VDCB_OK
AT83C26
Register name
SC1_STATUS
SC1_STATUS
SC1_STATUS
SC2_CFG0
SC3_CFG0
SC4_CFG0
SC5_CFG0
DCDCB
After the reading and the clear of the interrupt bits, several bits are used to control the status.
Table 5. Status bits description
The status for the ICARDERR1 and VCARDERRn (n= 1 to 5) bits is controlled with
VCARD_OKn bits.
The status for the ATRERRn (n= 1 to 5) is controlled by reading of values in CAPTURE_MSB
and CAPTURE_LSB.
The AT83C26 proposed a slew rate control on CIOn and CCLKn pins (n=1, 2, 3, 4, 5). The con-
trol operates on rising and falling edges of CCLKn and only on rising edge of CIOn.
Four modes are available:
•
•
SHUTDOWNA bit and SHUTDOWNB bit must be set to activate power down mode on DCDCA
and DCDCB converters.
If SHUTDOWNA = SHUTDOWNB = 1, the AT83C26 internal regulator also enters in power
down mode. The consumption is then about 30µA.
To exit from power down mode, TWI commands are needed to clear SHUTDOWNA and
SHUTDOWNB.
Automatic mode: The slew rate depends on VCARDn[1:0] value. The slew rate value is
optimized according to CVCCn.
Mode 1, 2 , 3 (1.8V, 3V, 5V): The user can forced the slew rate if needed. For example if
CVCCn = 5V, the user can program 1.8V or 3V to speed up the slew rate in case of long wire
connection between AT83C26 and smart cards.
Remark
Smart card presence in SC1
Smart card presence in SC2
CVCC1 voltage in range programmed in VCARD1[1:0]
CVCC2 voltage in range programmed in VCARD2[1:0]
CVCC3 voltage in range programmed in VCARD3[1:0]
CVCC4 voltage in range programmed in VCARD4[1:0]
CVCC5 voltage in range programmed in VCARD5[1:0]
CVCCB voltage in range programmed in VDCB[1:0]
7511D–SCR–02/07