Rainbow Electronics T89C5121 User Manual
Page 39
39
A/T8xC5121
4164G–SCR–07/06
Table 16. SCCON Register
SCCON (S:ACh, SCRS = 0)
Smart Card Contacts Register
Reset Value = 0X00 0000b
7
6
5
4
3
2
1
0
CLK
-
CARDC8
CARDC4
CARDIO
CARDCLK
CARDRST
CARDVCC
Bit Number Bit Mnemonic Description
7
CLK
Card Clock Selection
Clear this bit to use the CardClk bit (CARDCLK) to drive Card CLK pin.
Set this bit to use XTAL signal to drive the Card CLK pin.
Note:
internal synchronization avoids any glitch on the CLK pin when
switching this bit.
6
-
Reserved
The value read from this bit is indeterminate. Do not change this bit or write 0.
5
CARDC8
Card C8
Clear this bit to drive a low level on the Card C8 pin.
Set this bit to set a high level on the Card C8 pin.
4
CARDC4
Card C4
Clear this bit to drive a low level on the Card C4 pin.
Set this bit to set a high level on the Card C4 pin.
3
CARDIO
Card I/O
When the UART bit is cleared in SCICR Register, the value of this bit is
driven to the Card I/O pin.
Then this pin can be used as a pseudo bi-directional I/O when this bit is set.
To be used as an input, this bit must contain a 1.
2
CARDCLK
Card CLK
When the CLK bit is cleared in SCCON Register, the value of this bit is driven
to the Card CLK pin.
1
CARDRST
Card RST
Clear this bit to drive a low level on the Card RST pin.
Set this bit to set a high level on the Card RST pin.
Read is not allowed if VCARDOK=0
0
CARDV
CC
Card VCC Control
Clear this bit to desactivate the Card interface and set its power-off. The other
bits of SCC register have no effect while this bit is cleared.
Set this bit to power-on the Card interface. The activation sequence shall be
handled by software.