mc9s12vr48 Freescale Semiconductor, Inc, mc9s12vr48 Datasheet - Page 155

• Manufacturer Part Number: mc9s12vr48
• Description: S12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

4.3.2.20
Read: Anytime
Write: Anytime if PROT=0 (CPMUPROT register). Else write has no effect
Freescale Semiconductor
IRCTRIM[9:0]
TCTRIM[4:0]
0x02F8
0x02F9
After de-assert of System Reset a factory programmed trim value is automatically loaded from the Flash memory to
provide trimmed Internal Reference Frequency f
After de-assert of System Reset a factory programmed trim value is automatically loaded from the Flash memory to
provide trimmed Internal Reference Frequency f
Reset
Reset
15-11
Field
9-0
W
W
R
R
IRC1M temperature coefficient Trim Bits
Trim bits for the Temperature Coefficient (TC) of the IRC1M frequency.
Table 4-26
Figure 4-29
TCTRIM[4:0]=0x00000 or 0x10000).
IRC1M Frequency Trim Bits — Trim bits for Internal Reference Clock
After System Reset the factory programmed trim value is automatically loaded into these registers, resulting in a
Internal Reference Frequency f
The frequency trimming consists of two different trimming methods:
A rough trimming controlled by bits IRCTRIM[9:6] can be done with frequency leaps of about 6% in average.
A fine trimming controlled by bits IRCTRIM[5:0] can be done with frequency leaps of about 0.3% (this trimming
determines the precision of the frequency setting of 0.15%, i.e. 0.3% is the distance between two trimming
values).
Figure 4-28
S12CPMU_UHV IRC1M Trim Registers (CPMUIRCTRIMH /
CPMUIRCTRIML)
15
F
F
7
Writes to these registers while PLLSEL=1 clears the LOCK and UPOSC
status bits.
Figure 4-26. S12CPMU_UHV IRC1M Trim High Register (CPMUIRCTRIMH)
Figure 4-27. S12CPMU_UHV IRC1M Trim Low Register (CPMUIRCTRIML)
shows the influence of the bits TCTRIM[4:0] on the relationship between frequency and temperature.
shows an approximate TC variation, relative to the nominal TC of the IRC1M (i.e. for
shows the relationship between the trim bits and the resulting IRC1M frequency.
14
F
F
6
Table 4-25. CPMUIRCTRIMH/L Field Descriptions
MC9S12VR Family Reference Manual, Rev. 2.2
Preliminary - Subject to Change Without Notice
TCTRIM[4:0]
13
F
F
5
IRC1M_TRIM
IRC1M_TRIM
IRC1M_TRIM
.See device electrical characteristics for value of f
NOTE
12
F
F
4
.
.
IRCTRIM[7:0]
Description
Clock, Reset and Power Management (S12CPMU_UHV)
11
F
F
3
10
0
0
F
2
F
F
9
1
IRCTRIM[9:8]
IRC1M_TRIM
.
F
F
8
0
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