mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 23

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

1.4
1.4.1
Figure 1-3
functional units. Some modules in the microcontroller have selectable clock inputs. All memory-mapped
registers associated with the modules (except RGPIO) are clocked with BUSCLK. The RGPIO registers
are clocked with the CPU clock (MCGOUT).
Freescale Semiconductor
MCG
OSC
Note: The ADC has minimum and maximum frequency requirements. See the ADC chapter and the MCF51AC256 Series
Data Sheet. Flash memory has frequency requirements for program and erase operations. See the MCF51AC256 Series
Data Sheet.
* The fixed frequency clock (FFCLK) is internally synchronized to the bus clock (BUSCLK) and must not exceed one half of
the bus clock frequency.
System Clock Generation and Distribution
shows how clocks from the MCG and OSC are distributed to the microcontroller’s other
Clock Distribution Diagram
OSCOUT
MCGERCLK
MCGFFCLK
MCGOUT
MCGLCLK
1 kHz LPO
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
VBUS
LPOCLK
÷2
÷2
DBG
CPU
Figure 1-3. Clock Distribution Diagram
RAM
RTI
BUSCLK
SYNC*
COP
BDM
FFCLK*
TPM3
CAN
RGPIO
FTM1
FTM2
SCI2
SCI1
ADC
ACMP2
ACMP1
CRC
FLASH
SPI2
SPI1
Device Overview
IIC
1-7