mc9s08ac32 Freescale Semiconductor, Inc, mc9s08ac32 Datasheet - Page 173

• Manufacturer Part Number: mc9s08ac32
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

10.4.6
10.5
This section provides a functional description of each of the five operating modes of the ICG. Also
discussed are the loss of clock and loss of lock errors and requirements for entry into each mode. The ICG
is very flexible, and in some configurations, it is possible to exceed certain clock specifications. When
using the FLL, configure the ICG so that the frequency of ICGDCLK does not exceed its maximum value
to ensure proper MCU operation.
Freescale Semiconductor
Reset
Reset:
Field
Field
TRIM
POR
FLT
7:0
7
W
W
R
R
U = Unaffected by MCU reset
Functional Description
ICG Trim Register (ICGTRM)
Filter Value — The FLT bits indicate the current filter value, which controls the DCO frequency. The FLT bits are
read only except when the CLKS bits are programmed to self-clocked mode (CLKS = 00). In self-clocked mode,
any write to ICGFLTU updates the current 12-bit filter value. Writes to the ICGFLTU register will not affect FLT if
a previous latch sequence is not complete. The filter registers show the filter value (FLT).
ICG Trim Setting — The TRIM bits control the internal reference generator frequency. They allow a ±25%
adjustment of the nominal (POR) period. The bit’s effect on period is binary weighted (i.e., bit 1 will adjust twice
as much as changing bit 0). Increasing the binary value in TRIM will increase the period and decreasing the value
will decrease the period.
U
1
1
7
7
U
1
0
6
6
Figure 10-11. ICG Lower Filter Register (ICGFLTL)
Table 10-6. ICGFLTL Register Field Descriptions
Table 10-7. ICGTRM Register Field Descriptions
Figure 10-12. ICG Trim Register (ICGTRM)
MC9S08AC60 Series Data Sheet, Rev. 2
U
0
0
5
5
U
0
0
4
4
Description
Description
TRIM
FLT
U
3
0
3
0
Chapter 10 Internal Clock Generator (S08ICGV4)
0
0
U
2
2
U
0
0
1
1
U
0
0
0
0
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