M41T81MX6 STMicroelectronics, M41T81MX6 Datasheet
M41T81MX6
Specifications of M41T81MX6
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M41T81MX6 Summary of contents
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Features ■ For all new designs other than automotive, use M41T81S (contact the ST sales office for automotive grade) ■ Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century ■ 32 KHz crystal oscillator integrating ...
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Contents Contents 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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M41T81 List of tables Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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List of figures List of figures Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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M41T81 1 Description The M41T81 is a low-power serial RTC with a built-in 32.768 kHz oscillator (external crystal controlled). Eight bytes of the SRAM are used for the clock/calendar function and are configured in binary coded decimal (BCD) format. An ...
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Description Figure 2. 8-pin SOIC (M) connections Figure 3. Block diagram CRYSTAL OSCILLATOR SDA SCL BAT ( Open drain output 2. Square wave function has the highest priority on IRQ/FT/OUT/SQW output ...
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M41T81 2 Operation The M41T81 clock operates as a slave device on the serial bus. Access is obtained by implementing a start condition followed by the correct slave address (D0h). The 20 bytes contained in the device can then be ...
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Operation 2.1.2 Start data transfer A change in the state of the data line, from high to low, while the clock is high, defines the START condition. 2.1.3 Stop data transfer A change in the state of the data line, ...
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M41T81 Figure 4. Serial bus data transfer sequence CLOCK DATA START CONDITION Figure 5. Acknowledgement sequence SCL FROM MASTER DATA OUTPUT BY TRANSMITTER DATA OUTPUT BY RECEIVER 2.2 READ mode In this mode the master reads the M41T81 slave after ...
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Operation An alternate READ mode may also be implemented whereby the master reads the M41T81 slave without first writing to the (volatile) address pointer. The first address that is read is the last one stored in the pointer (see Figure ...
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M41T81 2.3 WRITE mode In this mode the master transmitter transmits to the M41T81 slave receiver. Bus protocol is shown in Figure 9 on page (R/W=0) is placed on the bus and indicates to the addressed device that word address ...
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Clock operation 3 Clock operation The 20-byte register map (see the date and time from the clock binary coded decimal format. Tenths/hundredths of seconds, seconds, minutes, and hours are contained within the first four registers. Note: The tenths/hundredths ...
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M41T81 Table 2. Clock register map Addr 00h 0.1 seconds 01h ST 10 seconds 02h 0 10 minutes 03h CEB CB 04h 0 0 05h 0 0 06h 0 0 07h 10 years 08h OUT FT 09h ...
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Clock operation 3.3 Calibrating the clock The M41T81 is driven by a quartz controlled oscillator with a nominal frequency of 32,768 Hz. The devices are tested not exceed ±35 ppm (parts per million) oscillator frequency error at 25 Figure 10 ...
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M41T81 The IRQ/FT/OUT/SQW pin is an open drain output which requires a pull-up resistor to V for proper operation. A 500-10 k resistor is recommended in order to control the rise time. The FT bit is cleared on power-down. Figure ...
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Clock operation 3.4 Setting alarm clock registers Address locations 0Ah-0Eh contain the alarm settings. The alarm can be configured to go off at a prescribed time on a specific month, date, hour, minute, or second or repeat every year, month, ...
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M41T81 Figure 13. Backup mode alarm waveform ABE and AFE Bits AF Bit in Flags Register IRQ/FT/OUT/SQW Table 3. Alarm repeat modes RPT5 RPT4 ...
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Clock operation 3.6 Square wave output The M41T81 offers the user a programmable square wave function which is output on the SQW pin. RS3-RS0 bits located in 13h establish the square wave output frequency. These frequencies are listed in completed, ...
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M41T81 3.8 Output driver pin When the FT bit, AFE bit, SQWE bit, and watchdog register are not set, the IRQ/FT/OUT/SQW pin becomes an output driver that reflects the contents the control register. In other words, when ...
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Maximum ratings 4 Maximum ratings Stressing the device above the rating listed in the absolute maximum ratings table may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other ...
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M41T81 5 DC and AC parameters This section summarizes the operating and measurement conditions, as well as the DC and AC characteristics of the device. The parameters in the following DC and AC characteristic tables are derived from tests performed ...
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... Battery supply voltage BAT I Battery supply current BAT 1. Valid for ambient operating temperature For IRQ/FT/OUT/SQW pin (open drain) 3. STMicroelectronics recommends the RAYOVAC BR1225 or BR1632 (or equivalent) as the battery supply. 4. After switchover (V 5. For rechargeable backup, V Table 10. Crystal electrical characteristics Sym f Resonant frequency ...
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M41T81 Table 11. Power down/up AC characteristics Symbol t SCL and SDA SCL and SDA at V rec 1. V fall time should not exceed 5 mV/µ Valid for ambient operating temperature: T Table ...
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DC and AC parameters Table 13. AC characteristics Sym f SCL clock frequency SCL t Clock low period LOW t Clock high period HIGH t SDA and SCL rise time R t SDA and SCL fall time F START condition ...
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M41T81 6 Package mechanical information In order to meet environmental requirements, ST offers these devices in different grades of ® ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available at: www.st.com. ...
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Package mechanical information Figure 17. SO8 – 8-lead plastic small package outline A2 Note: Drawing is not to scale. Table 14. SO8 – 8-lead plastic small outline (150 mils body width), package mechanical data Symbol ...
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M41T81 7 Part numbering Table 15. Ordering information scheme Example: Device type M41T Supply voltage and write protect voltage 2 Package M = SO8 Temperature range 6 = –40°C to 85°C Shipping ...
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Revision history 8 Revision history Table 16. Document revision history Date Dec-2001 21-Jan-2002 01-May-2002 05-Jun-2002 10-Jun-2002 03-Jul-2002 11-Oct-2002 21-Jan-2003 05-Mar-2003 12-Sep-2003 27-Apr-2004 17-Jun-2004 7-Sep-2004 13-Sep-2004 03-Jun-2005 22-Aug-2006 28-May-2008 11-Jun-2010 28/29 Revision 1 First issue 1.1 Fix table footnotes (Table 1.2 ...
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... M41T81 Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...