Main Clock Controller With Real Time Clock Mcc/Rtc; Programmable Cpu Clock Prescaler; Clock-Out Capability; Real Time Clock Timer (Rtc) - STMicroelectronics ST72361 Auto Series Manual

ST72361xx-Auto
10

Main clock controller with real time clock MCC/RTC

The Main Clock Controller consists of three different functions:
●
a programmable CPU clock prescaler
●
a clock-out signal to supply external devices
●
a real time clock timer with interrupt capability
Each function can be used independently and simultaneously.
10.1

Programmable CPU clock prescaler

The programmable CPU clock prescaler supplies the clock for the ST7 CPU and its internal
peripherals. It manages SLOW power saving mode (See
details).
The prescaler selects the f
MCCSR register: CP[1:0] and SMS.
10.2

Clock-out capability

The clock-out capability is an alternate function of an I/O port pin that outputs a f
to drive external devices. It is controlled by the MCO bit in the MCCSR register.
10.3

Real time clock timer (RTC)

The counter of the real time clock timer allows an interrupt to be generated based on an
accurate real time clock. Four different time bases depending directly on f
The whole functionality is controlled by 4 bits of the MCCSR register: TB[1:0], OIE and OIF.
When the RTC interrupt is enabled (OIE bit set), the ST7 enters ACTIVE HALT mode when
the HALT instruction is executed. See

Figure 38. Main clock controller (MCC/RTC) block diagram

main clock frequency and is controlled by three bits in the
CPU
f
OSC2
MCO CP1 CP0
MCCSR
DIV 2, 4, 8, 16
Doc ID 12468 Rev 3
Main clock controller with real time clock MCC/RTC
Section 7.2: Slow mode
Section 7.5: Active halt mode
RTC
COUNTER
SMS TB1 TB0 OIE OIF
for more
OSC2
are available.
OSC2
for more details.
MCO
TO
WATCHDOG
TIMER
MCC/RTC INTERRUPT
CPU CLOCK
f
CPU
TO CPU AND
PERIPHERALS
clock
87/279