MCP7940MT datasheet(11/38 Pages) MICROCHIP

Teilenummer	MCP7940MT

Bauteilbeschribung	Low-Cost I2C??Real-Time Clock/Calendar with SRAM

Download	38 Pages

Scroll/Zoom	100%

Hersteller	MICROCHIP [Microchip Technology]

Direct Link	http://www.microchip.com

Logo

11 / 38 page

 2012 Microchip Technology Inc.

Preliminary

DS22292A-page 11

MCP7940M

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. Bits 5:4

contain either the 10 hour in BCD for 24-hour format or

the AM/PM indicator and the 10-hour bit for 12-hour

format. Bit 5 determines the hour format. Setting this

bit to ‘0’ enables 24-hour format, setting this bit to ‘1’

enables 12-hour format.

0x03h – Contains the BCD day. The range is 1-7.

Additional bits are also used for configuration and

status.

• Bits 3:4 are not implemented.

• Bit 5 is the OSCON bit. This is set and cleared by

hardware. If this bit is set, the oscillator is running,

if cleared, the oscillator is not running. This bit

does not indicate that the oscillator is running at

the correct frequency. The RTCC will wait 32

oscillator cycles before the bit is set. The RTCC

will wait roughly 32 clock cycles to clear this bit.

0x04h – Contains the BCD date and 10 date. The

range is 01-31. Bits 5:4 contain the 10’s date and bits

4:0 contain the date.

0x05h – Contains the BCD month. Bit 4 contains the

10 month. Bit 5 is the Leap Year bit, which is set during

a leap year and is read-only.

0x06h – Contains the BCD year and 10 year. The

Range is 00-99.

0x07h – Is the Control register.

• Bit 7 is the OUT bit. This sets the logic level on the

MFP when not using this as a square wave out-

put.

• Bit 6 is the SQWE bit. Setting this bit enables the

divided output from the crystal oscillator.

• Bits 5:4 determine which alarms are active.

- 00 – No Alarms are active

- 01 – Alarm 0 is active

- 10 – Alarm 1 is active

- 11 – Both Alarms are active

• Bit 3 is the EXTOSC enable bit. Setting this bit will

allow an external 32.768 kHz signal to drive the

RTCC registers, eliminating the need for an

external crystal.

• Bit 2:0 sets the internal divider for the 32.768 kHz

oscillator to be driven to the MFP. The duty cycle is

50%. The output is responsive to the Calibration

register. The following frequencies are available:

- 000 – 1 Hz

- 001 – 4.096 kHz

- 010 – 8.192 kHz

- 011 – 32.768 kHz

- 1xx enables the Cal output function. Cal

output appears on MFP if SQWE is set (64

Hz Nominal). See Section 4.2.1 “Calibra-

tion” for more details.

0x08h is the Calibration register. This is an 8-bit

register that is used to add or subtract clocks from the

RTCC counter every minute. The MSB is the sign bit

and indicates if the count should be added or

subtracted. The remaining 7 bits, with each bit adding

or subtracting 2 clocks, give the user the ability to add

or subtract up to 254 clocks per minute.

0x0Ah-0x0fh and 0x11-0x16h are the Alarm 0 and

Alarm 1 registers. The bits are the same as the RTCC

bits with the following differences:

Locations 0x10h and 0x17h are reserved and should

not be used to allow for future device compatibility.

0x0Dh/0x14h has additional bits for alarm configu-

ration.

• ALMxPOL: This bit specifies the level that the

MFP will drive when the alarm is triggered.

ALM2POL is a copy of ALM1POL. The default

state of the MFP when used for alarms is the

inverse of ALM1POL.

• ALMxIF: This is the Alarm Interrupt Fag. This bit is

set in hardware if the alarm was triggered. The bit

is cleared in software.

Note:

The RTCC counters will continue to

increment during the calibration.

MCP7940MT Datenblatt(PDF) 11 Page - Microchip Technology

MCP7940MT Datenblatt(HTML) 11 Page - Microchip Technology

Ähnliche Teilenummer - MCP7940MT

Ähnliche Beschreibung - MCP7940MT

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

Datenblatt Download

Link URL