MAX7319 Ver la hoja de datos (PDF) - Maxim Integrated

Número de pieza

componentes Descripción

Fabricante

MAX7319

I2C Port Expander with Eight Inputs and Maskable Transition Detection

Maxim Integrated 

MAX7319

I2C Port Expander with Eight Inputs

and Maskable Transition Detection

Input port data is sampled during the preceding I2C

acknowledge bit (the acknowledge bit for the I2C slave

address in the case of a single-byte or 2-byte read).

A single-byte write to the MAX7319 sets the interrupt

mask register, and clears both the internal transition

flags and the INT output.

A multibyte write to the MAX7319 sets the interrupt

mask register repeatedly.

Reading from the MAX7319

A read from the MAX7319 starts with the master

transmitting the MAX7319’s slave address with the R/W

bit set high. The MAX7319 acknowledges the slave

address and samples the input ports during acknowledge

bit. INT deasserts during the slave address acknowledge.

Typically, the master reads 1 or 2 bytes from the MAX7319,

with each byte, except the last one, being acknowledged

by the master upon reception.

When the master reads 1 byte from the MAX7319 and

subsequently issues a STOP condition (Figure 6), the

MAX7319 transmits the current port data, clears the

transition flags, and resets the transition detection. INT

deasserts during the slave address acknowledge. The

new snapshot data is the current port data transmitted

to the master; therefore, port transitions ocurring during

the transmission are detected. INT remains high until the

STOP condition.

When the master reads 2 bytes from the MAX7319 and

subsequently issues a STOP condition (Figure 7), the

MAX7319 transmits the current port data, followed by

the transition flags. The transition flags are cleared, and

transition detection reset. INT deasserts during the

slave address acknowledge. The new snapshot data is

the current port data transmitted to the master; there-

fore, port transitions occurring during the transmission

are detected. INT remains high until the STOP condi-

tion. When the master reads more than 2 bytes, the input

port data alternates with the transition flag.

PORT INPUTS

I7 I6 I5 I4 I3 I2 I1 I0

INTERRUPT FLAGS

F7 F6 F5 F4 F3 F2 F1 F0

S 1 1 0 MAX7319 SLAVE ADDRESS 1 A D7 D6 D5 D4 D3 D2 D1 D0 A D7 D6 D5 D4 D3 D2 D1 D0 N P

SCL

PORTS

tIV

INT OUTPUT

R/W

PORT SNAPSHOT PORT SNAPSHOT

PORT SNAPSHOT

tPH

tPSU

tIP

tIR INT REMAINS HIGH UNTIL STOP CONDITION

S = START CONDITION

P = STOP CONDITION

SHADED = SLAVE TRANSMISSION

N = NOT ACKNOWLEDGE

Figure 7. Reading from the MAX7319 (2 Data Bytes)

www.maximintegrated.com

Maxim Integrated │  11

Share Link: