MAX7316 Ver la hoja de datos (PDF) - Maxim Integrated

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MAX7316

10-Port I/O Expander with LED Intensity Control, Interrupt, and Hot-Insertion Protection

Maxim Integrated 

10-Port I/O Expander with LED Intensity

Control, Interrupt, and Hot-Insertion Protection

WRITE TO OUTPUT PORTS REGISTERS (BLINK PHASE 0 REGISTERS/BLINK PHASE 1 REGISTERS)

SCL 1 2 3 4 5 6 7 8 9

SLAVE ADDRESS

COMMAND BYTE

SDA S A6 A5 A4 A3 A2 A1 A0 0 A 0 0 0 0 0 0 0 1 A MSB

DATA1

LSB A MSB

DATA2

LSB A P

START CONDITION

P7–P0

R/W ACKNOWLEDGE FROM SLAVE

ACKNOWLEDGE FROM SLAVE

ACKNOWLEDGE FROM SLAVE

DATA1 VALID

tDV

tDV

STOP

CONDITION

DATA2 VALID

READ FROM INPUT PORTS REGISTERS

SCL

123456789

SLAVE ADDRESS

COMMAND BYTE

SDA S A6 A5 A4 A3 A2 A1 A0 1 A MSB

DATA1

START CONDITION

P7–P0

DATA1

R/W ACKNOWLEDGE FROM SLAVE

DATA2

tDH

DATA3

LSB A MSB

DATA4

LSB NA P

ACKNOWLEDGE FROM MASTER

DATA4

tDS

STOP CONDITION

NO ACKNOWLEDGE FROM

MASTER

INTERRUPT VALID/RESET

SCL 1 2 3 4 5 6 7 8

SLAVE ADDRESS

SDA S A6 A5 A4 A3 A2 A1 A0 1

9

COMMAND BYTE

A MSB

DATA2

LSB A MSB

DATA4

LSB NA P

START CONDITION

P7–P0

DATA1

R/W ACKNOWLEDGE FROM SLAVE

DATA2

ACKNOWLEDGE FROM MASTER

DATA3

STOP CONDITION

NO ACKNOWLEDGE FROM

MASTER

INT

tIV

tIR tIV

tIR

Figure 10. Read, Write, and Interrupt Timing Diagrams

Message Format for Reading

The MAX7316 is read using the MAX7316’s internally

stored command byte as an address pointer the same

way the stored command byte is used as an address

pointer for a write. The pointer autoincrements after

each data byte is read using the same rules as for a

write (Table 2). Thus, a read is initiated by first configur-

ing the MAX7316’s command byte by performing a

write (Figure 7). The master can now read n consecu-

tive bytes from the MAX7316 with the first data byte

being read from the register addressed by the initial-

ized command byte. When performing read-after-write

verification, remember to reset the command byte’s

address because the stored command byte address

has been autoincremented after the write (Table 2). A

diagram of a read from the input ports register is shown

in Figure 10 reflecting the states of the ports.

Operation with Multiple Masters

If the MAX7316 is operated on a 2-wire interface with

multiple masters, a master reading the MAX7316 should

use a repeated start between the write, which sets the

MAX7316’s address pointer, and the read(s) that takes

the data from the location(s) (Table 2). This is because it

is possible for master 2 to take over the bus after master

1 has set up the MAX7316’s address pointer but before

master 1 has read the data. If master 2 subsequently

changes the MAX7316’s address pointer, then master

1’s delayed read can be from an unexpected location.

Command Address Autoincrementing

The command address stored in the MAX7316 circu-

lates around grouped register functions after each data

byte is written or read (Table 2).

10 ______________________________________________________________________________________

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