Technical Reference Manual 002-29852 Rev. *B
1.1.3 BACKUP_CAL_CTL
Description:
Oscillator calibration for absolute frequency
Address:
0x4027000C
Offset:
0xC
Retention:
Retained
IsDeepSleep:
No
Comment:
These bits are in vddbak domain. Calibration only works when the PRESCALER is set to
32768. Writes are ignored unless Write bit is set
Default:
0x0
Bit-field Table
Bits 7 6 5 4 3 2 1 0
Name None [7:7] CALIB_SIG
N [6:6]
CALIB_VAL [5:0]
Bits 15 14 13 12 11 10 9 8
Name None [15:8]
Bits 23 22 21 20 19 18 17 16
Name None [23:16]
Bits 31 30 29 28 27 26 25 24
Name CAL_OUT
[31:31]
None
[30:30]
CAL_SEL [29:28] None [27:24]
Bit-fields
Bits Name SW HW Default or
Enum
Description
0:5 CALIB_VAL RW A 0 Calibration value for absolute frequency (at a fixed
temperature). Each step causes 128 ticks to be added
or removed each hour. Effectively that means that
each step is 1.085ppm (= 128/(60*60*32,768)).
Positive values 0x01-0x3c (1..60) add pulses, negative
values remove pulses, thus giving a range of +/-65.1
ppm (limited by 60 minutes per hour, not the range of
this field)
Calibration is performed hourly, starting at 59 minutes
and 59 seconds, and applied as 64 ticks every 30
seconds until there have been 2*CALIB_VAL
adjustments.
6 CALIB_SIGN RW A 0 Calibration sign:
0= Negative sign: remove pulses (it takes more clock
ticks to count one second)
1= Positive sign: add pulses (it takes less clock ticks to
count one second)
28:29 CAL_SEL RW A 0 Select calibration wave output signal
CAL512 0 512Hz wave, not affected by calibration setting (not
supported for 50/60Hz input clock:
CTL.PRESCALER!=0)
RESERVED 1 N/A
CAL2 2 2Hz wave, includes the effect of the calibration setting,
(not supported for 50/60Hz input clock:
CTL.PRESCALER!=0)
CAL1 3 1Hz wave, includes the effect of the calibration setting
(supported for all input clocks)
31 CAL_OUT RW A 0 Output enable for wave signal for calibration and allow
CALIB_VAL to be written.
TRAVEO™ T2G Automotive MCU: TVII-B-E-4M body controller entry registers
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