RTC Programming Model
18-6
ADSP-BF537 Blackfin Processor Hardware Reference
RTC Programming Model
The RTC programming model consists of a set of system MMRs. Soft-
ware can configure the RTC and can determine the status of the RTC
through reads and writes to these registers. The RTC interrupt control
register (
RTC_ICTL
) and the RTC interrupt status register (
RTC_ISTAT
) pro-
vide RTC interrupt management capability.
Note that software cannot disable the RTC counting function. However,
all RTC interrupts can be disabled, or masked. At reset, all interrupts are
disabled. The RTC state can be read via the system MMR status registers
at any time.
The primary RTC functionality, shown in
sists of registers and counters that are powered by an independent RTC
V
dd
supply. This logic is never reset; it comes up in an unknown state
when RTC V
dd
is first powered on.
The RTC also contains logic powered by the same internal V
dd
as the pro-
cessor core and other peripherals. This logic contains some control
functionality, holding registers for PAB write data, and prefetched PAB
read data shadow registers for each of the five RTC V
dd
-powered registers.
This logic is reset by the same system reset and clocked by the same
SCLK
as the other peripherals.
shows the connections between the RTC V
dd
-powered RTC
MMRs and their corresponding internal V
dd
-powered write holding regis-
ters and read shadow registers. In the figure, “REG” means each of the
RTC_STAT
,
RTC_ALARM
,
RTC_SWCNT
,
RTC_ICTL
, and
RTC_PREN
registers.
The
RTC_ISTAT
register connects only to the PAB.
The rising edge of the 1 Hz RTC clock is the “1 Hz tick”. Software can
synchronize to the 1 Hz tick by waiting for the seconds event flag to set or
by waiting for the seconds interrupt (if enabled).
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 ...