Cmsemicon CMS32L051 - High-Speed Internal Oscillator Trim Register (HIOTRM)

V1.2.2
CMS32L051 User Manual |Chapter 4 Clock Generation Circuit
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4.3.9 High-speed internal oscillator trim register (HIOTRM)
This is a register to correct the accuracy of the high-speed internal oscillator. Self-measurement and
accuracy correction of the frequency of the internal oscillator at high speed can be performed using a timer
with a high-precision external clock input. The HIOTRM register is set via an 8-bit memory operation
instruction.
Note If the temperature and voltage at the V
DD
pin change after the accuracy is corrected, the frequency changes.
In the event of changes in temperature and voltage at the V
DD
pin, correction is required before the accuracy of
the required frequency or periodically.
Figure 4-11 Format of high-speed internal oscillator trim register (HIOTRM)
Address: 40021C00H After reset: Note R/W
Symbol
7 6 5 4 3 2 1 0
HIOTRM
HIOTRM5
HIOTRM4
HIOTRM3
HIOTRM2
HIOTRM1
HIOTRM0
High-speed internal
oscillator
0
0
0
0
0
0
Minimum speed
0
0
0
0
0
1
0
0
0
0
1
0
0
0
0
0
1
1
0
0
0
1
0
0



1
1
1
1
1
0
1
1
1
1
1
1
Maximum speed
Note The reset value is the adjustment value at the time of shipment.
Note 1. Each bit of the HIOTRM register can correct the clock accuracy of the high-speed internal oscillator by about
0.05%.
0
0
HIOTRM5
HIOTRM4
HIOTRM3
HIOTRM2
HIOTRM1
HIOTRM0