參數(shù)資料
型號: M41T60Q6F
廠商: STMICROELECTRONICS
元件分類: 時(shí)鐘/數(shù)據(jù)恢復(fù)及定時(shí)提取
英文描述: 1 TIMER(S), REAL TIME CLOCK, QCC16
封裝: 3 X 3 MM, LEAD FREE, QFN-16
文件頁數(shù): 5/27頁
文件大小: 534K
代理商: M41T60Q6F
M41T60
Clock operation
Doc ID 10396 Rev 12
These bits can be set to represent any value between 0 and 31 in binary format. Bit D5 is a
sign bit; '1' indicates positive calibration, '0' indicates negative calibration.
Calibration occurs within a 64-minute cycle. The first 62 minutes in the cycle may, once per
minute, have one second either shortened by 128 or lengthened by 256 oscillator cycles. If
a binary '1' is loaded into the register, only the first 2 minutes in the 64-minute cycle will be
modified; if a binary 6 is loaded, the first 12 will be affected, and so on. Therefore, each
calibration step has the effect of adding 512 or subtracting 256 oscillator cycles for every
125,829,120 actual oscillator cycles. That is, +4.068 or –2.034 ppm of adjustment per
calibration step in the calibration register. Assuming that the oscillator is running at exactly
32,768 Hz, each of the 31 increments in the calibration byte would represent +10.7 or –5.35
seconds per day which corresponds to a total range of +5.5 or –2.75 minutes per month.
Two methods are available for ascertaining how much calibration a given M41T60 may
require:
The first involves setting the clock, letting it run for a month and comparing it to a
known accurate reference and recording deviation over a fixed period of time.
Calibration values, including the number of seconds lost or gained in a given period,
can be found in application note AN934, “TIMEKEEPER calibration.” This allows the
designer to give the end user the ability to calibrate the clock as the environment
requires, even if the final product is packaged in a non-user serviceable enclosure. The
designer could provide a simple utility that accesses the calibration byte.
The second approach is better suited to a manufacturing environment, and involves the
use of the frequency test (FT) pin. The FT pin will toggle at 512 Hz when the ST bit is
set to '0,' and the OUT bit and FT bit are set to '1.' Any measured deviation from the
512 Hz frequency indicates the degree and direction of oscillator frequency shift at the
test temperature. For example, a reading of 512.010124 Hz would indicate a +20 ppm
oscillator frequency error, requiring a –10 (XX001010) to be loaded into the calibration
byte for correction.
Note:
Setting or changing the calibration byte does not affect the frequency test output frequency.
the FT pin is an open drain pin which requires a pull-up resistor to VCC for proper operation.
A 500-10 k resistor is recommended in order to control the rise time.
相關(guān)PDF資料
PDF描述
M44C510-P40 4-BIT, MROM, MICROCONTROLLER, PDIP40
M44C510D-XXX-DOW 4-BIT, MROM, MICROCONTROLLER
M44C588 4-BIT, MROM, 4 MHz, MICROCONTROLLER
M44C892 4-BIT, MROM, 4 MHz, MICROCONTROLLER, PDSO20
M48T08Y-15PC1 0 TIMER(S), REAL TIME CLOCK, PDMA28
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
M41T60Q6F-CUT TAPE 制造商:ST 功能描述:M41T60 Series 1.3 to 4.4 V Serial I2C Real Time Clock Surface Mount - QFN-16
M41T62 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Serial Access Real-Time Clock with Alarms
M41T62_06 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Serial Access Real-Time Clock with Alarms
M41T62_10 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Serial real-time clocks with alarm
M41T62_1112 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Serial real-time clocks (RTCs) with alarm