DS80C320-MCG Datasheet, PDF (30/175 Pages) Dallas Semiconductor – High-Speed Microcontroller User Guide

High-Speed Microcontroller User’s Guide
RTC Trim Register (TRIM)
7
6
5
4
3
2
1
0
SFR 91h E4K _{X12/ 6} TRM2 _TRM2 TRM1 TRM1
TRM0 TRM0
RT-* RT-*
RT-*
RT-*
RT-*
RT-*
RT-*
RT-*
R=Unrestricted Read, W=Unrestricted Write, -n=Value after Reset, *=See description
E4K
Bit 7
X12/ 6
Bit 6
TRM2
Bit 5
TRM2
Bit 4
TRM1
Bit 3
TRM1
Bit 2
TRM0
Bit 1
TRM0
Bit 0
External 4096 Hz RTC Signal Enable. This bit enables the output of a
4096 Hz signal on pin P1.7 derived from the RTC. Setting this bit overrides
any other function of the pin. It is used for adjusting the frequency of the
32.768 RTC crystal oscillator using the trim bits. This bit is cleared to 0
after any reset, including a no-battery reset.
0 = Calibration function disabled. P1.7 pin will function per the normal pin
description.
1 = 4096 Hz signal output on P1.7
RTC Crystal Capacitance Select. This bit selects the internal loading
capacitance of the RTC crystal amplifier. This bit is set to 1 after a no-battery
reset, and unchanged by all other forms of reset.
0 = RTC loading is set for 6 pF crystal.
1 = RTC loading is set for 12.5 pF crystal.
RTC Trim Bit 2. This bit controls the relative adjustment of the RTC internal
capacitance. It is used to calibrate the RTC oscillator frequency. This bit is set to
1 after a no-battery reset, and unchanged by all other forms of reset.
RTC Trim Bit 2. This bit controls the relative adjustment of the RTC internal
capacitance. It is used to calibrate the RTC oscillator frequency. This bit is set to
1 after a no-battery reset, and unchanged by all other forms of reset.
RTC Trim Bit 1. This bit controls the relative adjustment of the RTC internal
capacitance. It is used to calibrate the RTC oscillator frequency. This bit is set to
0 after a no-battery reset, and unchanged by all other forms of reset.
RTC Inverted Trim Bit 1. This bit must always be set to the complement of
the TRM1 bit. Incorrectly writing this bit will default bits TRIM.7, TRIM.5-0 to
their no-battery reset value. This bit is cleared to 1 after a no-battery reset, and
unchanged by all other forms of reset.
RTC Trim Bit 0. This bit controls the relative adjustment of the RTC internal
capacitance. It is used to calibrate the RTC oscillator frequency. This bit is set to
0 after a no-battery reset, and unchanged by all other forms of reset.
RTC Inverted Trim Bit 0. This bit must always be set to the complement of
the TRM0 bit. Incorrectly writing this bit will default bits TRIM.7, TRIM.5-0 to
their no-battery reset value. This bit is cleared to 1 after a no-battery reset, and
unchanged by all other forms of reset.
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