mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 444

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

Memory Map/Register Definition
20.3.8 MCG Auto Trim Control Register (MCG_ATC)
Address: MCG_ATC is FFFF_8400h base + 8h offset = FFFF_8408h
444
OSCINIT
CLKST
IRCST
ATME
Field
Reset
Field
3–2
Read
Write
1
0
7
Bit
ATME
Clock Mode Status
These bits indicate the current clock mode. The CLKST bits do not update immediately after a write to the
CLKS bits due to internal synchronization between clock domains.
00
01
10
11
OSC Initialization
This bit is set after the initialization cycles of the crystal oscillator clock have completed. Refer to the OSC
Block Guide for more details.
Internal Reference Clock Status
The IRCST bit indicates the current source for the internal reference clock select clock (IRCSCLK). The
IRCST bit does not update immediately after a write to the IRCS bit due to internal synchronization
between clock domains. The IRCST bit will only be updated if the internal reference clock is enabled,
either by the MCG being in a mode that uses the IRC or by setting the C1[IRCLKEN] bit .
0
1
Automatic Trim Machine Enable
Enables the Auto Trim Machine to start automatically trimming the selected Internal Reference Clock.
NOTE: ATME deasserts after the Auto Trim Machine has completed trimming all trim bits of the IRCS
Writing to C1, C3, C4, and ATC registers or entering Stop mode aborts the auto trim operation and clears
this bit.
0
1
7
0
Source of internal reference clock is the slow clock (32 kHz IRC).
Source of internal reference clock is the fast clock (2 MHz IRC).
Auto Trim Machine disabled.
Auto Trim Machine enabled.
Encoding 0 — Output of the FLL is selected (reset default).
Encoding 1 — Internal reference clock is selected.
Encoding 2 — External reference clock is selected.
Encoding 3 — Output of the PLL is selected.
clock selected by the ATMS bit.
ATMS
0
6
MCF51JF128 Reference Manual, Rev. 2, 03/2011
MCG_S field descriptions (continued)
MCG_ATC field descriptions
Table continues on the next page...
ATMF
0
5
Preliminary
0
4
Description
Description
0
3
0
0
2
Freescale Semiconductor, Inc.
0
1
0
0