AT83EC5123 ATMEL Corporation, AT83EC5123 Datasheet - Page 44

• Manufacturer Part Number: AT83EC5123
• Description: (AT8xx512x) Smart Card Reader ICs
• Manufacturer: ATMEL Corporation

Card Presence Input
SCIB Reset
44
AT8xC5122/23
The Clock signal CCLK1 can be adapted to the XTAL frequency. Thanks to the clock
prescaler which can divide the frequency by 1, 2, 4 or 8. The bits ALTKPS0 and
ALTKPS1 in SCSR Register are used to set this factor.
Figure 28. Alternate Card
The internal pull-up (weak pull-up) on Card Presence input can be disconnected in order
to reduce the consumption (CPRESRES, bit 3 in PMOD0).
In this case, an external resistor (typically 1 M ) must be externally tied to Vcc.
CPRES input can generate an interrupt (see Interrupt system section).
The detection level can be selected.
The SCICR register contains a reset bit. If set, this bit generates a reset of the SCI and
its registers. Table 38 defines the SCIB registers that are reset and their reset values.
Table 38. Reset Values for SCI Registers
Register Name
SCICR
SCCON
SCISR
SCIIR
SCIER
SCSR
SCTBUF
SCRBUF
SCETU1, SCETU0
SCGT1, SCGT0
SCWT3, SCWT2, SCWT1, SCWT0
SCICLK
FCK_IDLE
SCSR Reg.
ALTKPS0,1
PR3
1, 1/2, 1/4 or 1/8
P1.7
SCSR Reg.
SCCLK1
SCIB Reset Value (Binary)
0000 0000
0X00 0000
1000 0000
0X00 0000
0X00 0000
X000 1000
0000 0000
0000 0000
XXXX X001, 0111 0100 (372)
0000 0000, 0000 1100 (12)
0000 0000, 0000 0000, 0010 0101, 1000 0000 (9600)
0X10 1111
1
0
CVCC
CRST
CIO
CCLK
CPRES
CCLK1
SIM, SAM
SMART
CARD
CARD
4202B–SCR–07/03
Alternate
Main
card
card