MCP79411 datasheet(9/38 Pages) MICROCHIP

Part #	MCP79411

Description	I2C??Real-Time Clock/Calendar with EEPROM, SRAM, Unique ID and Battery Switchover

PDF	38 Pages

Scroll/Zoom	100%

Manufacturer	MICROCHIP [Microchip Technology]

Direct Link	http://www.microchip.com

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9 / 38 page

 2011 Microchip Technology Inc.

Preliminary

DS22266B-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. This involves the master sending a Start

condition, followed by the control byte for a write

command (R/W = 0). If the device is still busy with the

write cycle, then no ACK will be returned. If no ACK is

returned, then the Start bit and control byte must be

resent. If the cycle is complete, then the device will

return the ACK, and the master can then proceed with

the next read or write command. See Figure 3-4 for the

flow diagram.

FIGURE 3-4:

ACKNOWLEDGE

POLLING FLOW

Send

EE Write Command

Send Stop

Condition to

Initiate EE Write Cycle

Send Start

Send Control Byte

with R/W = 0

Did Device

Acknowledge

(ACK = 0)?

Operation

YES

MCP79411 Datasheet(PDF) 9 Page - Microchip Technology