At83c26 – Rainbow Electronics AT83C26 User Manual
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7511B–SCR–10/05
AT83C26
_
Reset value = 0x 0110 0000
Table 22. SC1_INTERFACE (Interface Byte for SC1)
7
6
5
4
3
2
1
0
0
IODIS1
CKSTOP1
CARDRST1
CARDC81
CARDC41
CARDCK1
CARDIO1
Bit Number
Bit Mnemonic
Description
7
0
This bit should not be set.
6
IODIS1
Card I/O isolation
Set this bit to drive the CIO1, CC41, CC81 pins according to CARDIO1, CARDC41, CARDC81
respectively.
Clear this bit to drive the CIO1, CC41 and CC81 pins connected to inputs according to IOSEL[3/0] bits.
5
CKSTOP1
CARD Clock Stop
Set this bit to stop CCLK1 according to CARDCK1. This can be used to set asynchronous cards in power-
down mode (GSM) or to drive CCLK1 by software.
Clear this bit to have CCLK1 running according to CKS1. This can be used to activate asynchronous cards.
Note:
When this bit is changed a special logic ensures that no glitch occurs on the CCLK1 pin and
actual configuration changes can be delayed by half a period to two periods of CCLK1.
4
CARDRST1
Card Reset
Set this bit to enter a reset sequence according to ART1 bit value.
Clear this bit to drive a low level on the CRST1 pin.
3
CARDC81
Card C8
Set this bit to drive the CC81 pin High with the on-chip pull-up (according to IODIS1 bit value). The pin can
then be an input (read in SC1_STATUS register).
Clear this bit to drive a low level on the CC81 pin (according to IODIS1 bit value).
2
CARDC41
Card C4
Set this bit to drive the CC41 pin High with the on-chip pull-up (according to IODIS1 bit value). The pin can
then be an input (read in SC1_STATUS register).
Clear this bit to drive a low level on the CC41 pin (according to IODIS1 bit value).
1
CARDCK1
Card Clock
Set this bit to set a high level on the CCLK1 pin (according to CKSTOP1 bit value).
Clear this bit to drive a low level on the CCLK1 pin.
0
CARDIO1
Card I/O
Set this bit to drive the CIO1 pin High with the on-chip pull-up (according to IODIS1 bit value). The pin can
then be an input (read in SC1_STATUS register).
Clear this bit to drive a low level on the CIO1 pin (according to IODIS1 bit value).