MAX17040 Просмотр технического описания (PDF) - Maxim Integrated

Номер в каталоге

Компоненты Описание

производитель

MAX17040

1-Cell/2-Cell Fuel Gauge with ModelGauge

Maxim Integrated 

MAX17040/MAX17041

1-Cell/2-Cell Fuel Gauge with ModelGauge

Table 5. 2-Wire Protocol Key

KEY

S

SAddr

MAddr

Data

A

N

DESCRIPTION

START bit

Slave address (7 bit)

Memory address byte

Data byte written by master

Acknowledge bit—master

No acknowledge—master

KEY

Sr

W

P

Data

A

N

DESCRIPTION

Repeated START

R/W bit = 0

STOP bit

Data byte returned by slave

Acknowledge bit—slave

No acknowledge—slave

Basic Transaction Formats

Write: S. SAddr W. A. MAddr. A. Data0. A. Data1. A. P

A write transaction transfers 2 or more data bytes to the

MAX17040/MAX17041. The data transfer begins at the

memory address supplied in the MAddr byte. Control of

the SDA signal is retained by the master throughout the

transaction, except for the acknowledge cycles:

Read: S. SAddr W. A. MAddr. A. Sr. SAddr R. A. Data0. A. Data1. N. P

Write Portion

Read Portion

A read transaction transfers 2 or more bytes from the

MAX17040/MAX17041. Read transactions are composed

of two parts, a write portion followed by a read portion,

and are therefore inherently longer than a write transac-

tion. The write portion communicates the starting point

for the read operation. The read portion follows immedi-

ately, beginning with a Repeated START, Slave Address

with R/W set to a 1. Control of SDA is assumed by the

MAX17040/MAX17041, beginning with the Slave Address

Acknowledge cycle. Control of the SDA signal is retained

by the MAX17040/MAX17041 throughout the transaction,

except for the acknowledge cycles. The master indicates

the end of a read transaction by responding to the last

byte it requires with a no acknowledge. This signals the

MAX17040/MAX17041 that control of SDA is to remain

with the master following the acknowledge clock.

Write Data Protocol

The write data protocol is used to write to register to

the MAX17040/MAX17041 starting at memory address

MAddr. Data0 represents the data written to MAddr,

Data1 represents the data written to MAddr + 1, and

DataN represents the last data byte, written to MAddr +

N. The master indicates the end of a write transaction by

sending a STOP or Repeated START after receiving the

last Acknowledge bit:

The MSB of the data to be stored at address MAddr can

be written immediately after the MAddr byte is acknowl-

edged. Because the address is automatically incremented

after the LSB of each byte is received by the MAX17040/

MAX17041, the MSB of the data at address MAddr + 1

can be written immediately after the acknowledgment of

the data at address MAddr. If the bus master continues an

autoincremented write transaction beyond address 4Fh,

the MAX17040/MAX17041 ignore the data. A valid write

must include both register bytes. Data is also ignored

on writes to read-only addresses. Incomplete bytes and

bytes that are not acknowledged by the MAX17040/

MAX17041 are not written to memory.

Read Data Protocol

The read data protocol is used to read to register from the

MAX17040/MAX17041 starting at the memory address

specified by MAddr. Both register bytes must be read

in the same transaction for the register data to be valid.

Data0 represents the data byte in memory location

MAddr, Data1 represents the data from MAddr + 1, and

DataN represents the last byte read by the master:

S. SAddr W. A. MAddr. A. Sr. SAddr R. A.

Data0. A. Data1. A... DataN. N. P

Data is returned beginning with the MSB of the data in

MAddr. Because the address is automatically increment-

ed after the LSB of each byte is returned, the MSB of the

data at address MAddr + 1 is available to the host imme-

diately after the acknowledgment of the data at address

MAddr. If the bus master continues to read beyond

address FFh, the MAX17040/MAX17041 output data val-

ues of FFh. Addresses labeled Reserved in the memory

map return undefined data. The bus master terminates

the read transaction at any byte boundary by issuing a no

acknowledge followed by a STOP or Repeated START.

S. SAddr W. A. MAddr. A. Data0. A. Data1. A... DataN. A. P

www.maximintegrated.com

Maxim Integrated │  11

Share Link: