ADSP-BF535 Blackfin Processor Hardware Reference
17-1
17 REAL-TIME CLOCK (RTC)
The Real-Time Clock (RTC) provides a set of digital watch features to the
ADSP-BF535 processor, including time of day, alarm, and stopwatch
countdown.
The RTC is clocked by a 32.768 kHz crystal external to the ADSP-BF535
processor. The RTC uses dedicated power supply pins, which enable it to
maintain functionality even when the rest of the ADSP-BF535 processor
is powered down.
The RTC input clock is divided down to a 1 Hz signal by a prescaler,
which can be bypassed. When bypassed, the RTC is clocked at the
32.768 kHz crystal rate. In normal operation, the prescaler is enabled.
The primary function of the RTC is to maintain an accurate day count
and time of day. The RTC accomplishes this by means of four counters:
• 60-second counter
• 60-minute counter
• 24-hour counter
• 255-day counter
The RTC increments the 60-second counter once per second and incre-
ments the other three counters when appropriate. The 255-day counter is
incremented each day at midnight (0 hours, 0 minutes, 0 seconds). The
RTC can generate an interrupt once per second, once per minute, and
once per day.
Summary of Contents for ADSP-BF535 Blackfin
Page 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Page 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Page 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Page 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Page 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Page 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Page 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Page 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Page 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...