cs5535 National Semiconductor Corporation, cs5535 Datasheet - Page 429

• Manufacturer Part Number: cs5535
• Description: Geode Cs5535 Companion Multi-function South Bridge
• Manufacturer: National Semiconductor Corporation

Revision 0.8
RTC Register Descriptions
5.15.2.13 RTC Control Register C (RTC_CRC)
I/O Address
Type
Reset Value
5.15.2.14 RTC Control Register D (RTC_CRD)
I/O Address
Type
Reset Value
Bit
7
6
5
4
3
IRQF
VRT
7
7
Name
IRQF (RO)
PF (RO)
AF (RO)
UF (RO)
RSVD (RO)
0Ch
RO
00h
PF
0Dh
RO
00h
6
6
Description
IRQ Flag (Read Only). This RO bit mirrors the value on the interrupt output signal.
When interrupt is active, IRQF is 1. Reading this register clears this bit (and deactivates
the interrupt pin) and clears the flag bits UF, AF, and PF.
0: IRQ inactive.
1: Logic equation is true: ((UIE and UF) or (AIE and AF) or (PIE and PF)).
Periodic Interrupts Flag (Read Only). This RO bit is cleared to 0 on an RTC reset
(i.e., hardware reset) or when the RTC is disabled. In addition, this bit is cleared to 0
when this register is read.
0: No transition occurred on the selected tap since the last read.
1: Transition occurred on the selected tap of the divider chain.
Alarm Interrupt Flag (Read Only). This RO bit is cleared to 0 as long as bit 7 of
RTC_CRD (VRT bit) is 0. In addition, this bit is cleared to 0 when this register is read.
0: No alarm detected since the last read.
1: Alarm condition detected.
Update Ended Interrupts Flag (Read Only). This RO bit is cleared to 0 on an RTC
reset (i.e., hardware reset) or when the RTC is disabled. In addition, this bit is cleared
to 0 when this register is read.
0: No update occurred since the last read.
1: Time registers updated.
Reserved (Read Only). Reads as 0.
AF
5
5
(Continued)
RTC_CRC Bit Descriptions
RTC_CRC Register Map
RTC_CRD Register Map
UF
4
4
429
RSVD
3
3
2
2
RSVD
1
1
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