M41T56 STMicroelectronics, M41T56 Datasheet
M41T56
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M41T56 Summary of contents
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... Operating temperature of –40°C to 85°C ■ Available in an 8-lead, 150mil, plastic SOIC (SO8) ■ RoHS compliant – Lead-free second level interconnect December 2007 Serial real-time clock with 56 bytes NVRAM C bus (100kHz Rev 8 M41T56 8 1 SO8 (M) 150mil width www.st.com 1/25 1 ...
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Contents 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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List of tables Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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List of figures Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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... Description The M41T56 is a low power, serial real-time clock with 56 bytes of NVRAM. A built-in 32,768Hz oscillator (external crystal controlled) and the first 8 bytes of the RAM are used for the clock/calendar function and are configured in binary coded decimal (BCD) format. Addresses and data are transferred serially via a two-line, bidirectional bus. The built-in address register is incremented automatically after each WRITE or READ data byte ...
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... FT/OUT BAT SCL SDA 6/25 Oscillator input Oscillator output Frequency test / output driver (open drain) Serial data address input / output Serial clock Battery supply voltage Supply voltage Ground M41T56 OSCI 1 8 OSCO BAT AI02306B OSCILLATOR DIVIDER 32 ...
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... Operation The M41T56 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 64 bytes contained in the device can then be accessed sequentially in the following order: 1. Seconds register 2. Minutes register 3. Century/hours register 4. Day register 5 ...
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Stop data transfer A change in the state of the data line, from Low to High, while the clock is High, defines the STOP condition. 2.1.4 Data valid The state of the data line represents valid data when after ...
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Figure 5. Acknowledge sequence START SCLK FROM 1 MASTER DATA OUTPUT MSB BY TRANSMITTER DATA OUTPUT BY RECEIVER Figure 6. Bus timing requirements sequence SDA tBUF tHD:STA tR SCL LSB tF tHIGH tSU:DAT tLOW tHD:DAT SR ...
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... SCL. 2.2 Read mode In this mode, the master reads the M41T56 slave after setting the slave address (see Figure 7 on page and the Acknowledge Bit, the word address A Next the START condition and slave address are repeated, followed by the READ Mode Control Bit (R ...
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Figure 7. Slave address location START Figure 8. Read mode sequence BUS ACTIVITY: MASTER SDA LINE S BUS ACTIVITY: SLAVE ADDRESS DATA n+X Figure 9. Alternative read mode sequence BUS ACTIVITY: MASTER SDA LINE S BUS ACTIVITY: SLAVE ADDRESS R/W ...
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... Write mode In this mode the master transmitter transmits to the M41T56 slave receiver. Bus protocol is shown in Figure 10 on page (R placed on the bus and indicates to the addressed device that word address A will follow and written to the on-chip address pointer. The data word to be written to the memory is strobed in next and the internal address pointer is incremented to the next memory location within the RAM on the reception of an acknowledge clock ...
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Clock operation The eight byte clock register (see and time from the clock binary coded decimal format. Seconds, Minutes, and Hours are contained within the first three registers. Bits D6 and D7 of Clock Register 2 (Hours ...
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... The devices are tested not to exceed 35 ppm (parts per million) oscillator frequency error at 25°C, which equates to about ±1.53 minutes per month. With the calibration bits properly set, the accuracy of each M41T56 improves to better than ±2 ppm at 25°C. The oscillation rate of any crystal changes with temperature (see Most clock chips compensate for crystal frequency and temperature shift error with cumbersome “ ...
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Figure 11. Crystal accuracy across temperature Frequency (ppm –20 –40 –60 –80 –100 –120 –140 –160 –40 –30 Figure 12. Clock calibration NORMAL POSITIVE CALIBRATION NEGATIVE CALIBRATION 3.2 Output driver pin When the FT Bit is not set, ...
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... These are stress ratings only and operation of the device at these or any other conditions above those indicated in the Operating sections of this specification is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE Program and other relevant quality documents. Table 4. ...
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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 under ...
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... For contact information on this crystal type, see References on page 2. Load capacitors are integrated within the M41T56. Circuit board layout considerations for the 32.768 kHz crystal of minimum trace lengths and isolation from RF generating signals should be taken into account. ...
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Table 9. Power down/up mode AC characteristics Symbol Parameter t SCL and SDA at V before power down (min PFD (min PFD CC ...
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Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK packages. These packages have a Lead-free second level interconnect. The category of second Level Interconnect is marked on the package and on the inner ...
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Figure 15. SO8 – 8-pin plastic small package outline Drawing is not to scale. Table 11. SO8 – 8-pin plastic small outline, package mechanical data millimetres Symbol Typ Min A A1 0.10 ...
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Part numbering Table 12. Ordering information scheme Example: Device type M41T Supply voltage and write protect voltage 4.5 to 5.5V CC Package M = SO8 Temperature range 6 = –40°C to 85°C Shipping method E ...
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References ● The crystal component supplier KDS as cited in characteristics on page 18 Table 8: Crystal electrical can be contacted at http://www.kds.info/index_en.htm 23/25 ...
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Revision history Table 13. Document revision history Date Revision Mar-1999 1.0 23-Dec-1999 1.1 21-Mar-2000 1.2 30-Nov-2000 1.3 25-Jan-2001 1.4 16-Feb-2001 2.0 06-Apr-2001 2.1 17-Jul-2001 2.2 02-Aug-2002 2.3 07-Nov-2002 2.4 15-Jun-2004 3.0 11-Sep-2006 4 09-Oct-2006 5 10-Apr-2007 6 06-Nov-2007 7 ...
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... 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. ...