ISL12022
22
FN6659.3
November 22, 2011
DST Day/Week Forward
DstDwFd contains both the Day of the Week and the Week of the
Month data for DST Forward control. DST can be controlled either
by actual date or by setting both the Week of the month and the
Day of the Week. DstDwFdE sets the priority of the Day/Week
over the Date. For DstDwFdE = 1, Day/Week is the priority. You
must have the correct Day of Week entered in the RTC registers
for the Day/Week correction to work properly.
Bits 0, 1, 2 contain the Day of the week information which sets
the Day of the Week that DST starts. Note that Day of the week
counts from 0 to 6, like the RTC registers. The default for the
DST Forward Day of the Week is 00h (normally Sunday).
Bits 3, 4, 5 contain the Week of the Month information that sets
the week that DST starts. The range is from 1 to 5, and Week 7
is used to indicate the last week of the month. The default for
the DST Forward Week of the Month is 00h.
DST Date Forward
DstDtfd controls which Date DST begins. The format for the Date
is the same as for the RTC register, from 1 to 31. The default
value for DST forward date is 00h. DstDtFd is only effective if
DstDwFdE = 0.
DST Hour Forward
DstHrFd controls the hour that DST begins. The RTC hour and
DstHrFd registers have the same formats except there is no
Military bit for DST hour. The user sets the DST hour with the
same format as used for the RTC hour (AM/PM or MIL) but
without the MIL bit, and the DST will still advance as if the MIL bit
were there. The default value for DST hour Forward is 00h.
DST REVERSE REGISTERS (24H TO 27H)
DST end (reverse) is controlled by the following DST Registers:
DST Month Reverse
DstMoRv sets the Month that DST ends. The format is the same
as for the RTC register month, from 1 to 12. The default value for
the DST end month is October (10h).
DST Day/Week Reverse
DstDwRv contains both the Day of the Week and the Week of the
Month data for DST Reverse control. DST can be controlled either
by actual date or by setting both the Week of the month and the
Day of the Week. DstDwRvE sets the priority of the Day/Week
over the Date. For DstDwRvE = 1, Day/Week is the priority. You
must have the correct Day of Week entered in the RTC registers
for the Day/Week correction to work properly.
Bits 0, 1, 2 contain the Day of the week information which sets
the Day of the Week that DST ends. Note that Day of the week
counts from 0 to 6, like the RTC registers. The default for the
DST Reverse Day of the Week is 00h (normally Sunday).
Bits 3, 4, 5 contain the Week of the Month information that
sets the week that DST ends. The range is from 1 to 5, and
Week 7 is used to indicate the last week of the month. The
default for the DST Reverse Week of the Month is 00h.
DST Date Reverse
DstDtRv controls which Date DST ends. The format for the Date is
the same as for the RTC register, from 1 to 31. The default value
for DST Date Reverse is 00h. The DstDtRv is only effective if the
DwRvE = 0.
DST Hour Reverse
DstHrRv controls the hour that DST ends. The RTC hour and
DstHrFd registers have the same formats except there is no
Military bit for DST hour. The user sets the DST hour with the
same format as used for the RTC hour (AM/PM or MIL) but
without the MIL bit, and the DST will still advance as if the MIL bit
were there. The default value for DST hour Reverse is 00h.
TEMP Registers (TEMP)
The temperature sensor produces an analog voltage output
which is input to an A/D converter and produces a 10-bit
temperature value in degrees Kelvin. TK07:00 are the LSBs of the
code, and TK09:08 are the MSBs of the code. The temperature
result is actually the average of two successive temperature
measurements to produce greater resolution for the temperature
control. The output code can be converted to degrees Centigrade
(°C) by first converting from binary to decimal, dividing by 2, and
then subtracting 273d, as shown in Equation
4:The practical range for the temp sensor register output is from 446d
to 726d, or -50°C to +90°C. The temperature compensation
function is only guaranteed over -40°C to +85°C. The TSE bit must
be set to “1” to enable temperature sensing.
NPPM Registers (NPPM)
The NPPM value is exactly 2x the net correction required to bring the
oscillator to 0ppm error. The value is the combination of oscillator
Initial Correction (IPPM) and crystal temperature dependent
correction (CPPM).
IPPM is used to compensate the oscillator offset at room
temperature and is controlled by the ITR0 and BETA registers,
which are fixed during factor test.
The CPPM compensates the oscillator frequency fluctuation over
temperature. It is determined by the temperature (T), crystal
curvature parameter (ALPHA), and crystal turnover temperature
(XT0). T is the result of the temp sensor/ADC conversion, whose
decimal result is 2x the actual temperature in Kelvin. ALPHA is
from either the ALPHA (cold) or ALPHAH (hot) register depending
on T, and XT0 is from the XT0 register.
TABLE 22.
TEMP
7654321
0
TK0L
TK07 TK06 TK05 TK04 TK03 TK02 TK01 TK00
TK0M
00
0000
TK09 TK08
Temperature in °C
[(TK <9:0>)/2] - 273
=
(EQ. 4)