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Chapter 1 MC9S12XF-Family Reference Manual
MC9S12XF - Family Reference Manual, Rev.1.19
Freescale Semiconductor
79
1.10
VREG Conguration
The VREGEN connection of the voltage regulator is tied internally to VDDR such that the voltage
regulator is always enabled with VDDR connected to a positive supply voltage. The device must be
congured with the internal voltage regulator enabled. Operation in conjunction with an external voltage
regulator is not supported.
The autonomous periodic interrupt clock output is mapped to PortT[5].
The API trimming register APITR is loaded on rising edge of RESET from the Flash IFR option eld at
global address 0x40_00F0 bits[5:0] during the reset sequence. Currently factory programming of this IFR
range is not supported.
1.10.1
Temperature Sensor Conguration
The VREG high temperature trimming register bits VREGHTTR[3:0] are loaded from the Flash IFR
option eld at global address 0x40_00F0 bits[11:8] during the reset sequence. To use the high temperature
interrupt within the specied limits (THTIA and THTID) these bits must be programmed to 0x8. Currently
factory programming of this IFR range is not supported. Note that the API trimming bits are also loaded
from 0x40_00F0[5:0].
The device temperature can be monitored on ADC0 channel[17].
The internal bandgap reference voltage can also be mapped to ADC0 analog input channel[17]. The
voltage regulator VSEL bit when set, maps the bandgap and, when clear, maps the temperature sensor to
ADC0 channel[17].
Read access to reserved VREG register space returns “0”. Write accesses have no effect. This device does
not support access abort of reserved VREG register space.
1.11
BDM Conguration
The BDM alternative clock corresponds to the oscillator clock.
1.12
FlexRay IPLL (CGMIPLL) Conguration
MC9S12XF512 features a dedicated internal PLL for the FlexRay protocol engine. The IPLL hard IP and
the register map for the conguration registers is identical to the system IPLL.
The usage of an dedicated internal PLL allows to use cheaper crystal devices and to achieve lower
radiation.
1.12.1
CGMIPLL function
The CGMIPLL module supplies the clock to the FlexRay controller. The FlexRay controller can only
operate according to FlexRay specication when it is supplied with stable 80MHz clock. The CGMIPLL