Specifications

ST72104Gx, ST72215Gx, ST72216Gx, ST72254Gx

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6.6 MAIN CLOCK CONTROLLER (MCC)

The Main Clock Controller (MCC) supplies the

clock for the ST7 CPU and its internal peripherals.

It allows SLOW power saving mode to be man

aged by the application.

All functions are managed by the Miscellaneous

The MCC block consists of:

■ A programmable CPU clock prescaler

■ A clock-out signal to supply external devices

The prescaler allows the selection of the main

clock frequency and is controlled by three bits of

the MISCR1: CP1, CP0 and SMS.

The clock-out capability consists of a dedicated

I/O port pin configurable as an f

CPU

clock output to

drive external devices. It is controlled by the MCO

bit in the MISCR1 register.

See Section 10 "MISCELLANEOUS REGIS-

TERS" on page 36 for more details.

Figure 14. Main Clock Controller (MCC) Block Diagram

DIV 2, 4, 8, 16

DIV 2

SMS

CP1 CP0

CPU CLOCK

MISCR1

CLOCK TO CAN

TO CPU AND

PERIPHERALS

OSC

CPU

MCO

PORT

FUNCTION

ALTERNATE

MCO ----

OSC

PERIPHERAL