BAT32G1x9 user manual | Chapter 4 Clock generation circuit
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Rev.1.02
4.7 High-speed internal vibration correction function
4.7.1
High-speed internal vibration self-adjustment function
This function measures the frequency of the high-speed internal oscillator using the sub-system clock fSUB
(32.768KHz) as the reference and corrects the frequency accuracy of the high-speed internal oscillator fHOCO
in real time.
Table 4-9is the operating specification of the high-speed internal vibration frequency correction function, and
Fig. 4-23is the action block diagram of the high-speed internal vibration frequency correction function.
Table 4-9
Operating specifications for the high-speed internal vibration frequency correction function
project
content
Reference clock
f
SUB
/2
9
(subsystem clock 32.768KHz).
target clock of
Correction
f
HOCO
(fast inner swing)
Action mode
Continuous action mode
A mode of continuous high-speed internal vibration frequency correction
Interval action mode
A mode that uses a timer clock end, etc., to perform high-speed internal vibration
frequency correction at intervals
Clock accuracy
adjustment function
Correction time: Correction period (31.2ms)
×
(number of corrections -0.5)
Note
interrupt
Interrupt when high-speed internal frequency correction is complete (when interrupt
permission is open)
Note: Correction time: Varies depending on the number of corrections.
Correction Period: The total time of the frequency determination phase and the frequency correction
phase.
Number of Corrections: The number of corrections by which the frequency is bound to the expected
value range.
Fig. 4-23 Action block diagram of high speed internal vibration frequency correction function
20 bit counter
Frequency
dividing circuit
Expected
value
circuit
Comparis
on circuit
Correction value [6:0]
CPU bus
Counter start
(CRCTL register: CRST bit)
fSUB/2^9
fSUB
(The counter starts to trigger)
Counting clock
fHOCO
Decrement
signal
Incremental
signal
SubOSC
32.768KHz
Clock correction
FRQSEL4-3
High speed internal
vibration correction
completion interrupt
(
INTCR
)
Option
Bytes
00C2H
High speed internal
vibration