Freescale Semiconductor Tower System Eval Kit for MC9S12GN32 TWR-S12GN32-KIT TWR-S12GN32-KIT Hoja De Datos
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TWR-S12GN32-KIT
S12 Clock, Reset and Power Management Unit (S12CPMU)
MC9S12G Family Reference Manual, Rev.1.23
Freescale Semiconductor
397
10.3.2.18 S12CPMU IRC1M Trim Registers (CPMUIRCTRIMH / CPMUIRCTRIML)
Read: Anytime
Write: Anytime if PROT=0 (CPMUPROT register). Else write has no effect
NOTE
Writes to these registers while PLLSEL=1 clears the LOCK and UPOSC
status bits.
status bits.
0x02F8
15
14
13
12
11
10
9
8
R
TCTRIM[4:0]
0
IRCTRIM[9:8]
W
Reset
F
F
F
F
0
0
F
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
provide trimmed Internal Reference Frequency f
IRC1M_TRIM
.
Figure 10-23. S12CPMU IRC1M Trim High Register (CPMUIRCTRIMH)
0x02F9
7
6
5
4
3
2
1
0
R
IRCTRIM[7:0]
W
Reset
F
F
F
F
F
F
F
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
provide trimmed Internal Reference Frequency f
IRC1M_TRIM
.
Figure 10-24. S12CPMU IRC1M Trim Low Register (CPMUIRCTRIML)
Table 10-22. CPMUIRCTRIMH/L Field Descriptions
Field
Description
15-11
TCTRIM[4:0]
IRC1M temperature coefficient Trim Bits
Trim bits for the Temperature Coefficient (TC) of the IRC1M frequency.
Trim bits for the Temperature Coefficient (TC) of the IRC1M frequency.
shows the influence of the bits TCTRIM4:0] on the relationship between frequency and
temperature.
shows an approximate TC variation, relative to the nominal TC of the IRC1M (i.e. for
TCTRIM[4:0]=0b00000 or 0b10000).
9-0
IRCTRIM[9:0]
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
After System Reset the factory programmed trim value is automatically loaded into these registers, resulting in a
Internal Reference Frequency f
IRC1M_TRIM
. See device electrical characteristics for value of f
IRC1M_TRIM
.
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 the 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).
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 the 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).
shows the relationship between the trim bits and the resulting IRC1M frequency.