MC9S08GB60A Datasheet, PDF (124/302 Pages) Freescale Semiconductor, Inc – HCS08 Microcontrollers

Internal Clock Generator (S08ICGV2)
7.5.1 ICG Control Register 1 (ICGC1)
7
6
5
4
3
2
1
0
R
HGO
W
RANGE
REFS
CLKS
0
OSCSTEN
LOCD
Reset
0
1
0
0
0
1
0
0
= Unimplemented or Reserved
Figure 7-12. ICG Control Register 1 (ICGC1)
Table 7-6. ICGC1 Field Descriptions
Field
Description
7
HGO
High Gain Oscillator Select — The HGO bit is used to select between low-power operation and high-amplitude
operation.
0 Oscillator configured for low power operation.
1 Oscillator configured for high amplitude operation.
6
RANGE
Frequency Range Select — The RANGE bit controls the oscillator, reference divider, and FLL loop prescaler
multiplication factor (P). It selects one of two reference frequency ranges for the ICG. The RANGE bit is
write-once after a reset. The RANGE bit only has an effect in FLL engaged external and FLL bypassed external
modes.
0 Oscillator configured for low frequency range. FLL loop prescale factor P is 64.
1 Oscillator configured for high frequency range. FLL loop prescale factor P is 1.
5
REFS
External Reference Select — The REFS bit controls the external reference clock source for ICGERCLK. The
REFS bit is write-once after a reset.
0 External clock requested.
1 Oscillator using crystal or resonator requested.
4:3
CLKS
Clock Mode Select — The CLKS bits control the clock mode. If FLL bypassed external is requested, it will not
be selected until ERCS = 1. If the ICG enters off mode, the CLKS bits will remain unchanged. Writes to the CLKS
bits will not take effect if a previous write is not complete.
The CLKS bits are writable at any time, unless the first write after a reset was CLKS = 0X, the CLKS bits cannot
be written to 1X until after the next reset (because the EXTAL pin was not reserved).
00 Self-clocked
01 FLL engaged, internal reference
10 FLL bypassed, external reference
11 FLL engaged, external reference
2
OSCSTEN
Enable Oscillator in Off Mode — The OSCTEN bit controls whether or not the oscillator circuit remains enabled
when the ICG enters off mode.
0 Oscillator disabled when ICG is in off mode unless ENABLE is high, CLKS = 10, and REFST = 1.
1 Oscillator enabled when ICG is in off mode, CLKS = 1X and REFST = 1.
1
LOCD
Loss of Clock Disable
0 Loss of clock detection enabled.
1 Loss of clock detection disabled.
MC9S08GB60A Data Sheet, Rev. 2
124
Freescale Semiconductor