ADSP-BF537 Blackfin Processor Hardware Reference
18-15
Real-Time Clock
interrupts are needed immediately after reset, it is recommended to write
RTC_ICTL
to
0x0000
so that later read-modify-write accesses function as
intended.
Interrupt status can be determined by reading the RTC interrupt status
register (
RTC_ISTAT
). All bits in
RTC_ISTAT
are sticky. Once set by the cor-
responding event, each bit remains set until cleared by a software write to
this register. Event flags are always set; they are not masked by the inter-
rupt enable bits in
RTC_ICTL
. Values are cleared by writing a 1 to the
respective bit location, except for the write pending status bit, which is
read-only. Writes of 0 to any bit of the register have no effect. This regis-
ter is cleared at reset and during deep sleep.
The RTC interrupt is set whenever an event latched into the
RTC_ISTAT
register is enabled in the
RTC_ICTL
register. The pending RTC interrupt is
cleared whenever all enabled and set bits in
RTC_ISTAT
are cleared, or when
all bits in
RTC_ICTL
corresponding to pending events are cleared.
As shown in
, the RTC generates an interrupt request (IRQ)
to the processor core for event handling and wakeup from a sleep state.
The RTC generates a separate signal for wakeup from a deep sleep or from
an internal V
dd
power-off state. The deep sleep wakeup signal is asserted
at the 1 Hz tick when any RTC interval event enabled in
RTC_ICTL
occurs.
The assertion of the deep sleep wakeup signal causes the processor core
clock (
CCLK
) and the system clock (
SCLK
) to restart. Any enabled event that
asserts the RTC deep sleep wakeup signal also causes the RTC IRQ to
assert once
SCLK
restarts.
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...