Rainbow Electronics AT83C26 - Manual (Page 50)

50
7511B–SCR–10/05
AT83C26
Reset value = 0x 000X X000
Table 29. SC4_CFG0()
7 6 5 4 3 2 1 0
VCARD_INT4 VCARD_OK4 ATRERR4 X X VCARDERR4 VCARD41 VCARD40
Bit Number Bit Mnemonic Description
7 VCARD_INT4
SC4 voltage interrupt
This bit is set when VCARD_OK4 bit is set.
This bit is cleared when read by the micro controller.
6 VCARD_OK4
SC4 Voltage Status
This bit is set by the LD04 when the output voltage remains within the voltage range specified by
VCARD4[1:0] bits.
It is cleared otherwise.
5 ATRERR4
Answer to Reset Interrupt for SC4
This bit is set when the card clock counter overflows (no falling edge on CIO4 is received before the
overflow of the card clock counter).
This bit is cleared by hardware when this register is read. It can be set by software for test purpose.
4 X
3 X
2 VCARDERR4
Interface 4 Card Out of Range Voltage Interrupt
This bit is set when the output voltage on CVCC
N
goes out of the voltage range specified by VCRDN field. It
can be set by software for test purpose and deactivate the card.
This bit is cleared by hardware when this register is read. It cannot be cleared by software.
The reset value is 0.
1-0 VCARD4[1:0]
Interface 4 Card Voltage Selection
VCRD4[1:0] = 00: 0V
VCRD4[1:0] = 01: 1.8V class C
VCRD4[1:0] = 10: 3V class B
VCRD4[1:0] = 11: 5V class A
No card deactivation is performed when the voltage is changed. The micro controller should deactivate the
card before changing the voltage and activating the card again.
The reset value is 00.