Clock Trim Register (Clktrim) (For Factory Test Use Only, Except Hfo_Ln_Filter_En) Register; Trim And Test Registers - Note - Texas Instruments UCD3138 Technical Reference Manual

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9.13 Trim and Test Registers - Note

There are several trim and test registers in the Miscellaneous Analog Control register set.
It is highly recommended that nearly all of the bit-fields in these registers be
untouched by a customer program. There is one exception:
• For the best clock accuracy over temperature, the HFO_LN_FILTER_EN bit
in the CLKTRIM register should be cleared.
The data sheet specification for clock performance is characterized with this bit
cleared. It is necessary for the customer program to clear this bit, since the
default value is for this bit to be set.
9.13.1 Clock Trim Register (CLKTRIM) (For Factory Test Use Only, Except
HFO_LN_FILTER_EN)
Address FFF7F000
Figure 9-16. Clock Trim Register (CLKTRIM) (For Factory Test Use Only, Except
14 13 12
HFO_CLK_TRIM
R/W-011 1000
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 9-21. Clock Trim Register (CLKTRIM) (For Factory Test Use Only, Except
Bit Field
14-8 HFO_CLK_TRIM
7-6 HFO_SEL_
RANGE
5 HFO_LN_FILTER
_EN
4 LFO_DISABLE
3-1 HFO_THERM
_TRIM
0 HFO_ENABLE
SNIU028A – February 2016 – Revised April 2016
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HFO_LN_FILTER_EN)
11 10 9 8
HFO_LN_FILTER_EN) Register Field Descriptions
Type Reset
R/W 011 1000 High Frequency Oscillator Clock Trim Bits. Register will be programmed during test
and should not be overwritten by firmware
R/W 10
High Frequency Oscillator Range Select Bits. Register will be programmed during
test and should not be overwritten by firmware.
R/W 1
High Frequency Oscillator Low Noise Filter. Register should be cleared by firmware.
R/W 0
Low Frequency Oscillator Disable. Register will be programmed during test and
should not be overwritten by firmware.
0 = Low Frequency Oscillator Enabled (Default)
1 = Low Frequency Oscillator Disabled
R/W 011
High Frequency Oscillator Thermal Coefficient Trim Bits. Register will be
programmed during test and should not be overwritten by firmware
R/W 1
High Frequency Oscillator Enable. Register will be programmed during test and
should not be overwritten by firmware.
0 = High Frequency Oscillator Disabled
1 = High Frequency Oscillator Enabled (Default)
Copyright © 2016, Texas Instruments Incorporated
CAUTION
7 6 5 4
HFO_SEL_ HFO_ LFO_
RANGE LN_FIL DISAB
TER_E LE
N
R/W-10 R/W-1 R/W-0
Description
Advanced Power Management Control Functions
Trim and Test Registers - Note
3 2 1 0
HFO_THERM_TRIM HFO_E
NABLE
R/W-011 R/W-1
351