Datasheet

Device Overview MC9S12G-Family

MC9S12G Family Reference Manual, Rev.1.23

44 Freescale Semiconductor

• Interrupt ﬂag register for pin interrupts on ports P, J and AD

• Control register to conﬁgure

IRQ pin operation

• Routing register to support programmable signal redirection in 20 TSSOP only

• Routing register to support programmable signal redirection in 100 LQFP package only

• Package code register preset by factory related to package in use, writable once after reset. Also

includes bit to reprogram routing of API_EXTCLK in all packages.

• Control register for free-running clock outputs

•

1.3.5 Main External Oscillator (XOSCLCP)

• Loop control Pierce oscillator using a 4 MHz to 16 MHz crystal

— Current gain control on amplitude output

— Signal with low harmonic distortion

— Low power

— Good noise immunity

— Eliminates need for external current limiting resistor

— Transconductance sized for optimum start-up margin for typical crystals

— Oscillator pins can be shared w/ GPIO functionality

1.3.6 Internal RC Oscillator (IRC)

• Trimmable internal reference clock.

— Frequency: 1 MHz

— Trimmed accuracy over –40˚C to +125˚C ambient temperature range:

±1.0% for temperature option C and V (see Table A-4)

±1.3% for temperature option M (see Table A-4)

1.3.7 Internal Phase-Locked Loop (IPLL)

• Phase-locked-loop clock frequency multiplier

— No external components required

— Reference divider and multiplier allow large variety of clock rates

— Automatic bandwidth control mode for low-jitter operation

— Automatic frequency lock detector

— Conﬁgurable option to spread spectrum for reduced EMC radiation (frequency modulation)

— Reference clock sources:

– External 4–16 MHz resonator/crystal (XOSCLCP)

– Internal 1 MHz RC oscillator (IRC)