mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 374

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

Multipurpose Clock Generator (MCGV3)
16.3.2
16-6
EREFSTEN
ERCLKEN
RANGE
EREFS
Field
BDIV
HGO
7:6
LP
5
4
3
2
1
0
Reset:
W
R
MCG Control Register 2 (MCGC2)
Bus Frequency Divider — Selects the amount to divide down the clock source selected by the CLKS bits in the
MCGC1 register. This controls the bus frequency.
00
01
10
11
Frequency Range Select — Selects the frequency range for the crystal oscillator or external clock source.
1 High frequency range selected for the crystal oscillator of 1 MHz to 16 MHz (1 MHz to 40 MHz for external
0 Low frequency range selected for the crystal oscillator of 32 kHz to 100 kHz (32 kHz to 1 MHz for external
High Gain Oscillator Select — Controls the crystal oscillator mode of operation.
1 Configure crystal oscillator for high gain operation
0 Configure crystal oscillator for low power operation
Low Power Select — Controls whether the FLL (or PLL) is disabled in bypassed modes.
1 FLL (or PLL) is disabled in bypass modes (lower power)
0 FLL (or PLL) is not disabled in bypass modes.
External Reference Select — Selects the source for the external reference clock.
1 Oscillator requested
0 External Clock Source requested
External Reference Enable — Enables the external reference clock for use as MCGERCLK.
1 MCGERCLK active
0 MCGERCLK inactive
External Reference Stop Enable — Controls whether or not the external reference clock remains enabled when
the MCG enters stop mode.
1 External reference clock stays enabled in stop if ERCLKEN is set or if MCG is in FEE, FBE, PEE, PBE, or
0 External reference clock is disabled in stop
clock source)
clock source)
BLPE mode before entering stop
Encoding 0 — Divides selected clock by 1
Encoding 1 — Divides selected clock by 2 (reset default)
Encoding 2 — Divides selected clock by 4
Encoding 3 — Divides selected clock by 8
0
7
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
BDIV
Table 16-4. MCG Control Register 2 Field Descriptions
1
6
Figure 16-3. MCG Control Register 2 (MCGC2)
RANGE
5
0
HGO
0
4
Description
.
LP
3
0
EREFS
0
2
ERCLKEN EREFSTEN
Freescale Semiconductor
1
0
0
0