mc9s12q128 Freescale Semiconductor, Inc, mc9s12q128 Datasheet - Page 57

• Manufacturer Part Number: mc9s12q128
• Description: Hcs12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

1.4
The clock and reset generator provides the internal clock signals for the core and all peripheral modules.
Figure 1-13
Guide for details on clock generation.
1.5
Eight possible modes determine the device operating configuration. Each mode has an associated default
memory map and external bus configuration controlled by a further pin.
Three low power modes exist for the device.
1.5.1
The operating mode out of reset is determined by the states of the MODC, MODB, and MODA pins during
reset. The MODC, MODB, and MODA bits in the MODE register show the current operating mode and
provide limited mode switching during operation. The states of the MODC, MODB, and MODA pins are
latched into these bits on the rising edge of the reset signal. The ROMCTL signal allows the setting of the
ROMON bit in the MISC register thus controlling whether the internal Flash is visible in the memory map.
ROMON = 1 mean the Flash is visible in the memory map. The state of the ROMCTL pin is latched into
the ROMON bit in the MISC register on the rising edge of the reset signal.
Freescale Semiconductor
System Clock Description
Modes of Operation
Chip Configuration Summary
shows the clock connections from the CRG to all modules. Consult the CRG Block User
EXTAL
XTAL
CRG
Figure 1-13. Clock Connections
Bus Clock
Oscillator Clock
MC9S12Q128
Rev 1.09
Chapter 1 MC9S12Q Device Overview (MC9S12Q128-Family)
Core Clock
Not on 9S12GC
S12_CORE
MSCAN
VREG
Flash
RAM
ATD
TPM
TIM
PIM
SCI
SPI
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