Datasheet

ManualsBrandsMicrochip ManualsClockRTC IC SOIC I²C/2-Wire Serial

 2010 Microchip Technology Inc. Preliminary DS22266A-page 1

MCP79410/MCP79411/MCP79412

Device Selection Table

Features:

• Real-Time Clock/Calendar (RTCC), Battery

Backed:

- Hours, Minutes, Seconds, Day of Week, Day,

Month and Year

- Dual alarm with single output

• On-Chip Digital Trimming/Calibration:

- Range -127 to +127 ppm

- Resolution 1 ppm

• Programmable Open-Drain Output Control:

- CLKOUT with 4 selectable frequencies

- Alarm output

• 64 Bytes SRAM, Battery Backed

• 1 Kbits EEPROM (128x8):

- 8 bytes/page

- Block/sector write protection

- Protect none, 1/4, 1/2 or all of array

• Separate 64-Bit Unique ID:

- User or factory programmable

- Protected area

-EUI-48

™

or EUI-64

™

MAC address

- Custom ID programming

• Automatic V

CC Switchover to VBAT Backup

Supply

• Power-Fail Time-Stamp for Battery Switchover

• Low-Power CMOS Technology:

- Dynamic Current: 400 A max read

- Dynamic Current: 3mA max EEPROM write

- Battery Backup Current: <700nA @ 1.8V

• 100 kHz and 400 kHz Compatibility

• ESD Protection >4,000V

• More than 1 Million Erase/Write Cycles

• Packages include 8-Lead SOIC, TSSOP, 2x3

TDFN, MSOP

• Pb-Free and RoHS Compliant

• Temperature Ranges:

- Industrial (I): -40°C to +85°C.

Description:

The MCP7941X series of low-power Real-Time Clocks

(RTC) uses digital timing compensation for an accurate

clock/calendar, a programmable output control for

versatility, a power sense circuit that automatically

switches to the backup supply, and nonvolatile memory

for data storage. Using a low-cost 32.768 kHz crystal,

it tracks time using several internal registers. For

communication, the MCP7941X uses the I

C™ bus.

The clock/calendar automatically adjusts for months

with fewer than 31 days, including corrections for

leap years. The clock operates in either the 24-hour

or 12-hour format with an AM/PM indicator and

settable alarm(s) to the second, minute, hour, day of

the week, date or month. Using the programmable

CLKOUT, frequencies of 32.768, 8.192 and 4.096

kHz and 1 Hz can be generated from the external

crystal.

Along with the on-board Serial EEPROM and battery-

backed SRAM memory, a 64-bit protected space is

available for a unique ID or MAC address to be

programmed at the factory or by the end user.

The device is fully accessible through the serial

interface while V

CC is between 1.8V and 5.5V, but can

operate down to 1.3V for timekeeping and SRAM

retention only.

The RTC series of devices are available in the standard

8-lead SOIC, TSSOP, MSOP and 2x3 TDFN packages.

Package Types

Part

Number

EEPROM

(Kbits)

SRAM

(Bytes)

Unique ID

MCP79410 1K 64 Blank

MCP79411 1K 64 EUI-48

™

MCP79412 1K 64 EUI-64

™

BAT

VSS

VCC

MFP

SCL

SDA

MSOP

SOIC, TSSOP

BAT

VSS

MFP

SCL

SDA

TDFN

BAT

VSS

MFP

SCL

SDA

C™ Real-Time Clock/Calendar with EEPROM, SRAM,

Unique ID and Battery Switchover

Summary of content (34 pages)

PAGE 1
MCP79410/MCP79411/MCP79412 I2C™ Real-Time Clock/Calendar with EEPROM, SRAM, Unique ID and Battery Switchover Device Selection Table Description: Part Number EEPROM (Kbits) SRAM (Bytes) Unique ID MCP79410 1K 64 Blank MCP79411 1K 64 EUI-48™ MCP79412 1K 64 EUI-64™ Features: • Real-Time Clock/Calendar (RTCC), Battery Backed: - Hours, Minutes, Seconds, Day of Week, Day, Month and Year - Dual alarm with single output • On-Chip Digital Trimming/Calibration: - Range -127 to +127 ppm - Resolution 1
PAGE 2
MCP7941X FIGURE 1-1: TYPICAL OPERATING CIRCUIT RTCC Oscillator X1 Time-Stamp/ Alarms VDD SRAM X2 VBAT MFP VBAT Switch VSS DS22266A-page 2 EEPROM I2C™ ID SCL SDA Preliminary  2010 Microchip Technology Inc.
PAGE 3
MCP7941X 1.0 ELECTRICAL CHARACTERISTICS Absolute Maximum Ratings (†) VCC.............................................................................................................................................................................6.5V All inputs and outputs w.r.t. VSS ..........................................................................................................-0.6V to VCC +1.0V Storage temperature .................................................................................
PAGE 4
MCP7941X TABLE 1-2: AC CHARACTERISTICS Electrical Characteristics: Industrial (I): VCC = +1.8V to 5.5V AC CHARACTERISTICS Param. Symbol No. Characteristic Min. Max. Units TA = -40°C to +85°C Conditions 1 FCLK Clock frequency — — 100 400 kHz 1.8V  VCC < 2.5V 2.5V  VCC  5.5V 2 THIGH Clock high time 4000 600 — — ns 1.8V  VCC < 2.5V 2.5V  VCC  5.5V 3 TLOW Clock low time 4700 1300 — — ns 1.8V  VCC < 2.5V 2.5V  VCC  5.
PAGE 5
MCP7941X FIGURE 1-2: BUS TIMING DATA 5 SCL 7 SDA In D4 2 3 8 9 4 10 6 13 11 12 SDA Out  2010 Microchip Technology Inc.
PAGE 6
MCP7941X 2.0 PIN DESCRIPTIONS The descriptions of the pins are listed in Table 2-1. FIGURE 2-1: DEVICE PINOUTS SOIC/DFN/MSOP/TSSOP 2.1 X1 1 8 Vcc X2 2 7 MFP VBAT 3 6 SCL Vss 4 5 SDA Serial Data (SDA) This is a bidirectional pin used to transfer addresses and data into and out of the device. It is an open-drain terminal, therefore, the SDA bus requires a pull-up resistor to VCC (typically 10 k for 100 kHz, 2 k for 400 kHz).
PAGE 7
MCP7941X 3.0 I2C™ BUS CHARACTERISTICS 3.1.1.4 3.1 I2C Interface The state of the data line represents valid data when, after a Start condition, the data line is stable for the duration of the high period of the clock signal. The MCP7941X supports a bidirectional 2-wire bus and data transmission protocol. A device that sends data onto the bus is defined as transmitter, and a device receiving data as receiver.
PAGE 8
MCP7941X FIGURE 3-2: ACKNOWLEDGE TIMING Acknowledge Bit 1 SCL 2 3 SDA 4 5 6 7 8 9 1 Receiver must release the SDA line at this point so the Transmitter can continue sending data. DEVICE ADDRESSING AND OPERATION selected. The next byte received defines the address of the data byte (Figure 3-3). The upper address bits are transferred first, followed by the Least Significant bits (LSb). A control byte is the first byte received following the Start condition from the master device (Figure 3-2).
PAGE 9
MCP7941X 3.1.3 ACKNOWLEDGE POLLING Since the device will not acknowledge an EEPROM command during an EEPROM write cycle, this can be used to determine when the cycle is complete. This feature can be used to maximize bus throughput. Once the Stop condition for a write command has been issued from the master, the device initiates the internally timed write cycle. ACK polling can be initiated immediately.
PAGE 10
MCP7941X 4.0 RTCC FUNCTIONALITY The shaded areas are not implemented and read as ‘0’. No error checking is provided when loading time and date registers. The MCP7941x family is a highly integrated RTCC. Onboard time and date counters are driven from a lowpower oscillator to maintain the time and date. An integrated VCC switch enables the device to maintain the time and date and also the contents of the SRAM during a VCC power failure. 4.1 • Addresses 0x00h-0x06h are the RTCC Time and Date registers.
PAGE 11
MCP7941X 4.1.1 RTCC REGISTER ADDRESSES 0x00h – Contains the BCD seconds and 10 seconds. The range is 00 to 59. Bit 7 in this register is used to start or stop the on-board crystal oscillator. Setting this bit to a ‘1’ starts the oscillator and clearing this bit to a ‘0’ stops the on-board oscillator. 0x01h – Contains the BCD minutes and 10 minutes. The range is 00 to 59. 0x02h – Contains the BCD hour in bits 3:0.
PAGE 12
MCP7941X 4.2 • ALMxC2:0: These Configuration bits determine the alarm match. The logic will trigger the alarm based on one of the following match conditions: 4.2.1 000 – Seconds match 001 – Minutes match 010 – Hours match (takes into account 12/24 hour) 011 – Matches the current day, interrupt at 12.00.00 a.m. Example: 12 midnight on 100 – Date 101 – RESERVED 110 – RESERVED 111 – Seconds, Minutes, Hour, Day, Date, Month • The 12/24-hour bits 0xCh.6 and 0x13h.
PAGE 13
MCP7941X 4.2.3 CALIBRATION The MCP7941X utilizes digital calibration to correct for inaccuracies of the input clock source (either external or crystal). Calibration is enabled by setting the value of the Calibration register at address 08H. Calibration is achieved by adding or subtracting a number of input clock cycles per minute in order to achieve ppm level adjustments in the internal timing function of the MCP7941X.
PAGE 14
MCP7941X In the case where the MSB of the Calibration register is set to ‘1’, the MFP output waveforms that appear when bits RS1 and RS0 are set to ‘01’ or ‘10’ are not as responsive to the setting of the Calibration register. For example, when outputting the 4.096 kHz waveform (RS1, RS0 set to ‘01’), the output waveform is generated using only eight input clock cycles.
PAGE 15
MCP7941X 4.2.7 POWER-FAIL TIME-STAMP The MCP7941X family of RTCC devices feature a power-fail time-stamp feature. This feature will save the time at which VCC crosses the VTRIP voltage. To use this feature, a VBAT supply must be present and the oscillator must also be running. There are two separate sets of registers that are used to record this information: • The first set located at 0x18h through 0x1Bh are loaded at the time when VCC fails and the RTCC operates on the VBAT.
PAGE 16
MCP7941X 5.0 ON BOARD MEMORY removed, provided the VBAT supply is present and enabled. The EEPROM is organized as 128 x 8 bytes. The EEPROM is nonvolatile memory and does not require the VBAT supply for retention. The MCP7941X has both on-board EEPROM memory and Battery-Backed SRAM. The SRAM is arranged as 64 x 8 bytes and is retained when the VCC supply is 5.
PAGE 17
MCP7941X 5.2 5.2.1 EEPROM EEPROM BYTE WRITE Following the Start condition from the master, the control code and the R/W bit (which is a logic low) are clocked onto the bus by the master transmitter. This indicates to the addressed slave receiver that a byte with a word address will follow after it has generated an Acknowledge bit during the ninth clock cycle. Therefore, the next byte transmitted by the master is the word address and will be written into the Address Pointer of the MCP7941X.
PAGE 18
MCP7941X FIGURE 5-3: EE BYTE WRITE BUS ACTIVITY MASTER SDA LINE S T A R T CONTROL BYTE S10 1 0111 0 ADDRESS BYTE DATA x P A C K x = don’t care for 1K devices A C K BUS ACTIVITY FIGURE 5-4: S T O P A C K EE PAGE WRITE BUS ACTIVITY MASTER SDA LINE S T A R T CONTROL BYTE ADDRESS BYTE DATA BYTE 7 DATA BYTE 0 x S101 01110 P A C K A C K A C K BUS ACTIVITY S T O P A C K x = don’t care for 1K devices 5.2.
PAGE 19
MCP7941X 5.2.4.3 Sequential Read master, the master will NOT generate an Acknowledge but will generate a Stop condition. To provide sequential reads, the MCP7941X contains an internal Address Pointer which is incremented by one at the completion of each operation. This Address Pointer allows the entire memory contents to be serially read during one operation. The internal Address Pointer will automatically roll over to the start of the Block.
PAGE 20
MCP7941X 6.0 PACKAGING INFORMATION 6.1 Package Marking Information 8-Lead SOIC (3.90 mm) Example: XXXXXT XXYYWW NNN 79410I SN e3 0527 13F Example: 8-Lead TSSOP XXXX 7941 TYWW I527 NNN 13F Example: 8-Lead MSOP XXXXX 79401I YWWNNN 52713F 8-Lead 2x3 TDFN Example: XXX YWW NN AC4 527 13 1st Line Marking Codes Part Number TSSOP MSOP MCP79410 7941 79410T AAP MCP79411 9411 79411T AAQ 9412 79412T AAR MCP79412 Note: Legend: XX...
PAGE 21
MCP7941X /HDG 3ODVWLF 6PDOO 2XWOLQH 61 ± 1DUURZ PP %RG\ >62,&@ 1RWH )RU WKH PRVW FXUUHQW SDFNDJH GUDZLQJV SOHDVH VHH WKH 0LFURFKLS 3DFNDJLQJ 6SHFLILFDWLRQ ORFDWHG DW KWWS ZZZ PLFURFKLS FRP SDFNDJLQJ D e N E E1 NOTE 1 1 2 3 α h b h A2 A c φ L A1 L1 8QLWV 'LPHQVLRQ /LPLWV 1XPEHU RI 3LQV β 0,//,0(7(56 0,1 1 120 0$; 3LWFK H 2YHUDOO +HLJKW $ ± %6& ± 0ROGHG 3DFNDJH 7KLFNQHVV $ ± ± 6WDQGRII $ ± 2YHUDOO :LGWK ( 0ROGHG 3DFNDJH :LGWK (
PAGE 22
MCP7941X /HDG 3ODVWLF 6PDOO 2XWOLQH 61 ± 1DUURZ PP %RG\ >62,&@ 1RWH )RU WKH PRVW FXUUHQW SDFNDJH GUDZLQJV SOHDVH VHH WKH 0LFURFKLS 3DFNDJLQJ 6SHFLILFDWLRQ ORFDWHG DW KWWS ZZZ PLFURFKLS FRP SDFNDJLQJ DS22266A-page 22 Preliminary  2010 Microchip Technology Inc.
PAGE 23
MCP7941X /HDG 3ODVWLF 7KLQ 6KULQN 6PDOO 2XWOLQH 67 ± PP %RG\ >76623@ 1RWH )RU WKH PRVW FXUUHQW SDFNDJH GUDZLQJV SOHDVH VHH WKH 0LFURFKLS 3DFNDJLQJ 6SHFLILFDWLRQ ORFDWHG DW KWWS ZZZ PLFURFKLS FRP SDFNDJLQJ D N E E1 NOTE 1 1 2 b e c A φ A2 A1 L L1 8QLWV 'LPHQVLRQ /LPLWV 1XPEHU RI 3LQV 0,//,0(7(56 0,1 1 120 0$; 3LWFK H 2YHUDOO +HLJKW $ ± %6& ± 0ROGHG 3DFNDJH 7KLFNQHVV $ 6WDQGRII $ ± 2YHUDOO :LGWK ( 0ROGHG 3DFNDJH :LGWK (
PAGE 24
MCP7941X /HDG 3ODVWLF 0LFUR 6PDOO 2XWOLQH 3DFNDJH 06 >0623@ 1RWH )RU WKH PRVW FXUUHQW SDFNDJH GUDZLQJV SOHDVH VHH WKH 0LFURFKLS 3DFNDJLQJ 6SHFLILFDWLRQ ORFDWHG DW KWWS ZZZ PLFURFKLS FRP SDFNDJLQJ D N E E1 NOTE 1 1 2 e b A2 A c φ L L1 A1 8QLWV 'LPHQVLRQ /LPLWV 1XPEHU RI 3LQV 0,//,0(7(56 0,1 1 120 0$; 3LWFK H 2YHUDOO +HLJKW $ ± %6& ± 0ROGHG 3DFNDJH 7KLFNQHVV $ 6WDQGRII $ ± 2YHUDOO :LGWK ( 0ROGHG 3DFNDJH :LGWK ( %6& 2YHUDO
PAGE 25
MCP7941X /HDG 3ODVWLF 'XDO )ODW 1R /HDG 3DFNDJH 01 ± [ [ PP %RG\ >7')1@ 1RWH )RU WKH PRVW FXUUHQW SDFNDJH GUDZLQJV SOHDVH VHH WKH 0LFURFKLS 3DFNDJLQJ 6SHFLILFDWLRQ ORFDWHG DW KWWS ZZZ PLFURFKLS FRP SDFNDJLQJ  2010 Microchip Technology Inc.
PAGE 26
MCP7941X /HDG 3ODVWLF 'XDO )ODW 1R /HDG 3DFNDJH 01 ± [ [ PP %RG\ >7')1@ 1RWH )RU WKH PRVW FXUUHQW SDFNDJH GUDZLQJV SOHDVH VHH WKH 0LFURFKLS 3DFNDJLQJ 6SHFLILFDWLRQ ORFDWHG DW KWWS ZZZ PLFURFKLS FRP SDFNDJLQJ DS22266A-page 26 Preliminary  2010 Microchip Technology Inc.
PAGE 27
MCP7941X APPENDIX A: REVISION HISTORY Revision A (10/2010) Original release of this document.  2010 Microchip Technology Inc.
PAGE 28
MCP7941X NOTES: DS22266A-page 28 Preliminary  2010 Microchip Technology Inc.
PAGE 29
MCP7941X THE MICROCHIP WEB SITE CUSTOMER SUPPORT Microchip provides online support via our WWW site at www.microchip.com. This web site is used as a means to make files and information easily available to customers.
PAGE 30
MCP7941X READER RESPONSE It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150. Please list the following information, and use this outline to provide us with your comments about this document.
PAGE 31
MCP7941X PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. Not every possible ordering combination is listed below. X PART NO. Device Device: /XX Examples: Temperature Package Range MCP79410 = MCP79410T = MCP79411 = MCP79411T = MCP79412 = MCP79412T = 1.8V - 5.5V I2C™ Serial RTCC 1.8V - 5.5V I2C Serial RTCC 1.8V - 5.5V I2C Serial RTCC, EUI-48TM 1.8V - 5.5V I2C Serial RTCC, EUI-48TM (Tape and Reel) 1.8V - 5.
PAGE 32
MCP7941X NOTES: DS22266A-page 32 Preliminary  2010 Microchip Technology Inc.
PAGE 33
Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature.
PAGE 34
Worldwide Sales and Service AMERICAS ASIA/PACIFIC ASIA/PACIFIC EUROPE Corporate Office 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: http://support.microchip.com Web Address: www.microchip.