sc9s08mz16 Freescale Semiconductor, Inc, sc9s08mz16 Datasheet - Page 131

• Manufacturer Part Number: sc9s08mz16
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

8.4.4
8.5
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
Freescale Semiconductor
Reset
Reset:
POR
Field
Field
Field
TRIM
FLT
FLT
3:0
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.
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 8-10. ICG Lower Filter Register (ICGFLTL)
Table 8-5. ICGFLTU Register Field Descriptions
Table 8-6. ICGFLTL Register Field Descriptions
Table 8-7. ICGTRM Register Field Descriptions
Figure 8-11. ICG Trim Register (ICGTRM)
SC9S08MZ16 MCU Data Sheet, Rev. 1
U
0
0
5
5
U
0
0
4
4
Description
Description
Description
TRIM
FLT
U
3
0
3
0
0
0
U
2
2
Internal Clock Generator (S08ICGV4)
0
0
U
1
1
U
0
0
0
0
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