ST72T311R6T1 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
ST72T311R6T1
STMicroelectronics
'ST72T311R6T1' PDF : 164 Pages View PDF
ST72311R, ST72511R, ST72512R, ST72532R
10.2 MAIN CLOCK CONTROLLER WITH REAL TIME CLOCK TIMER (MCC/RTC)
The Main Clock Controller consists of three differ-
ent functions:
s a programmable CPU clock prescaler
s a clock-out signal to supply external devices
s a real time clock timer with interrupt capability
Each function can be used independently and si-
multaneously.
10.2.1 Programmable CPU Clock Prescaler
The programmable CPU clock prescaler supplies
the clock for the ST7 CPU and its internal periph-
erals. It manages SLOW power saving mode (See
Section 7.2 ”SLOW MODE” on page 34 for more
details).
The prescaler selects the fCPU main clock frequen-
cy and is controlled by three bits in the MISCR1
register: CP[1:0] and SMS.
CAUTION: The prescaler does not act on the CAN
peripheral clock source. This peripheral is always
supplied by the fOSC/2 clock source.
10.2.2 Clock-out Capability
The clock-out capability is an alternate function of
an I/O port pin that outputs a fOSC/2 clock to drive
external devices. It is controlled by the MCO bit in
the MISCR1 register.
CAUTION: When selected, the clock out pin sus-
pends the clock during ACTIVE-HALT mode.
10.2.3 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 depend-
ing directly on fOSC are available. The whole func-
tionality is controlled by four 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 Section 7.4
”ACTIVE-HALT AND HALT MODES” on page 36
for more details.
Figure 29. Main Clock Controller (MCC/RTC) Block Diagram
fOSC/2
PORT
ALTERNATE
FUNCTION
MISCR1
- - MCO -
- CP1 CP0 SMS
CLOCK TO CAN
PERIPHERAL
MCO
fOSC
DIV 2
RTC
COUNTER
MCCSR
0 0 0 0 TB1 TB0 OIE OIF
MCC/RTC INTERRUPT
DIV2, 4, 8, 16
fCPU
CPU CLOCK
TO CPU AND
PERIPHERALS
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