MCP79520 datasheet(17/58 Pages) MICROCHIP

Part #	MCP79520

Description	Battery-Backed SPI Real-Time Clock/Calendar

PDF	58 Pages

Scroll/Zoom	100%

Manufacturer	MICROCHIP [Microchip Technology]

Direct Link	http://www.microchip.com

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17 / 58 page

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DS20002300D-page 17

MCP7951X/MCP7952X

5.3.2

GENERATING HUNDREDTH OF

SECONDS

A special algorithm is required to accurately generate

hundredth of seconds. The circuitry utilizes the

4.096 kHz clock signal and counts 41 clock pulses

each for 24 increments of the hundredth of seconds

count. The circuitry then counts 40 clock pulses for the

next increment of the hundredth of second count. This

results in every 25 hundredth of seconds increments

equaling exactly 250 ms. Long term, the hundredth of

seconds frequency will average the desired 100 Hz,

while jitter is minimized short term.

EQUATION 5-2:

HUNDREDTH OF

SECONDS GENERATION

41 clocks 24 counts





40 clocks 1 count





4,096 Hz

---------------------------------------------------------------------------------------------------------------

250 ms

MCP79520 Datasheet(PDF) 17 Page - Microchip Technology