44
Agere Systems Inc.
T8302 Internet Protocol Telephone
Advanced RISC Machine (
ARM
)
Data Sheet
July 2001
4 Reset/Clock Management
(continued)
4.2.14 RTC Seconds Alarm Register
The real-time clock interrupt
(see Table 26 on page 51)
is asserted when the values in the
RTC seconds alarm
register
(Table 18) and
RTC seconds count register
(Table 19)
are equal. If the RTC interrupt is enabled
(
AI ENA
) in the
RTC
interrupt enable register
(see Table 22 on page 45)
and in the PIC (programmable interrupt
controller), an interrupt to the processor will occur. The
RTC seconds alarm register
is reset to 0 during powerup
reset, or hardware reset, but this register is not affected by the other reset sources. Table 18 shows the format of
the
RTC seconds alarm register
.
Table 18. RTC Seconds Alarm Register
4.2.15 RTC Seconds Count Register
The
RTC seconds count register
shows the current time in seconds. If
UCP
is 1 when read, an update occurred
and the value is invalid and should be read again. Updates occur once per second. Table 19 shows the format of
the
RTC seconds count register
.
Table 19. RTC Seconds Count Register
4.2.16 RTC Divider Register
The
RTC divider register
contains a count of the clocks that have occurred since the last time the
RTC seconds
count register
(Table 19) was updated. This register is incremented once per input clock cycle. This register is
written only during testing, when
IE
of the
RTC control register
(see Table 17 on page 43)
is set to 0. Otherwise,
an interrupt illegal write error is generated. Table 20 shows the format of the
RTC divider register
.
Address 0xE000 C004
Bit #
Name
Bit #
31:29
28:0
31:29
RSVD
28:0
SA
Name
RSVD Reserved.
SA
Represents time in clock ticks.
Description
Address 0xE000 C008
Bit #
Name
Bit #
31
31
UCP
30:29
RSVD
Description
28:0
SC
Name
UCP
Update cycle occurred.
If 1, an update cycle occurred during a read access.
If 0, the value returned was stable.
RSVD Reserved.
SC
Represents time in clock ticks.
30:29
28:0