MAX7310 Ver la hoja de datos (PDF) - Maxim Integrated

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MAX7310

2-Wire-Interfaced 8-Bit I/O Port Expander with Reset

Maxim Integrated 

2-Wire-Interfaced 8-Bit I/O Port Expander

with Reset

Table 1. Register Address

REGISTER

ADDRESS

(hex)

0x00

0x01

0x02

0x03

0x04

FUNCTION

PROTOCOL

Input port register Read byte.

Output port register Read/write byte.

Polarity inversion

register

Read/write byte.

Configuration

register

Timeout register

Read/write byte.

Read/write byte.

0xFF

Reserved register

Factory reserved.

Do not write to this

register.

Table 2. Register 0—Input Port Register

BIT I7 I6 I5 I4 I3 I2 I1 I0

The output port register sets the outgoing logic levels of

the I/O ports, defined as outputs by the configuration

register. Reads from the output port register reflect the

value that is in the flip-flop controlling the output selec-

tion, not the actual I/O value, which may differ if the out-

put is overloaded.

The polarity inversion register enables polarity inversion

of ports defined as inputs by the configuration register.

Set the bit in the polarity inversion register (write with a

1) to invert the corresponding port pin’s polarity. Clear

the bit in the polarity inversion register (write with a

zero) to retain the corresponding port pin’s original

polarity.

The configuration register configures the directions of

the ports. Set the bit in the configuration register to

enable the corresponding port pin as an input with a

high-impedance output driver. Clear the bit in the con-

figuration register to enable the corresponding port pin

as an output.

Set bit T0 to enable the bus timeout function and low to

disable the bus timeout function. Enabling the timeout

feature resets the serial bus interface when SCL stops

either high or low during a read or write access to the

MAX7310. If either SCL or SDA is low for more than

30ms min and 60ms max after the start of a valid serial

transfer, the interface resets itself. Resetting the serial

bus interface sets up SDA as an input. The MAX7310

then waits for another start condition.

Standby

The MAX7310 goes into standby when all pins are set

to V+ or GND. Standby supply current is typically

1.7µA.

Table 3. Register 1—Output Port Register

BIT

Default

O7

O6

O5

O4

O3

O2

O1

O0

0

0

0

0

0

0

0

0

Table 4. Register 2—Polarity Inversion Register

BIT

Default

I/O7

I/O6

I/O5

I/O4

I/O3

I/O2

I/O1

I/O0

1

1

1

1

0

0

0

0

Table 5. Register 3—Configuration Register

BIT

Default

I/O7

I/O6

I/O5

I/O4

I/O3

I/O2

I/O1

I/O0

1

1

1

1

1

1

1

1

Table 6. Register 4—Timeout Register

BIT

Default

T7

T6

T5

T4

T3

T2

T1

T0

x

x

x

x

x

x

x

1

8 _______________________________________________________________________________________

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