Command Address Autoincrementing

The command address stored in the MAX7313 circu-

lates around grouped register functions after each data

byte is written or read (Table 2).

Device Reset

If a device reset input is needed, consider the

MAX7314. The MAX7314 includes a RST input, which

clears any transaction to or from the MAX7314 on the

serial interface and configures the internal registers to

the same state as a power-up reset.

Detailed Description

Initial Power-Up

On power-up all control registers are reset and the

MAX7313 enters standby mode (Table 3). Power-up

status makes all ports into inputs and disables both the

PWM oscillator and blink functionality.

Configuration Register

The configuration register is used to configure the PWM

intensity mode, interrupt, and blink behavior, operate

the INT/O16 output, and read back the interrupt status

(Table 4).

16-Port I/O Expander with LED Intensity

Control, Interrupt, and Hot-Insertion Protection

12

______________________________________________________________________________________

Figure 10. Read, Write, and Interrupt Timing Diagrams

SLAVE ADDRESS

1

2

3

4567

89

S A6 A5 A4 A3 A2 A1 A00

A

0

0

0

00

00

COMMAND BYTE

1A

A

A

P

START CONDITION

ACKNOWLEDGE FROM SLAVE

ACKNOWLEDGE FROM SLAVE

ACKNOWLEDGE FROM SLAVE

STOP

CONDITION

P7–P0

P15– P8

DATA1 VALID

DATA2 VALID

SLAVE ADDRESS

1

2

3

4567

89

S A6A5A4A3A2A1A0

1

A

COMMAND BYTE

ANA

START CONDITION

ACKNOWLEDGE FROM SLAVE

ACKNOWLEDGE FROM MASTER

P7–P0

P15–P8

STOP CONDITION

P

NO ACKNOWLEDGE FROM

MASTER

DATA2

DATA4

DATA3

SLAVE ADDRESS

1

2

3

4567

89

S A6A5A4A3A2A1A0 1

A

COMMAND BYTE

ANA

START CONDITION

ACKNOWLEDGE FROM SLAVE

ACKNOWLEDGE FROM MASTER

P7–P0

P15–P8

STOP CONDITION

P

NO ACKNOWLEDGE FROM

MASTER

DATA1

DATA2

DATA3

DATA4

DATA6

DATA5

DATA1

SCL

SDA

SCL

SDA

SCL

SDA

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

READ FROM INPUT PORTS REGISTERS

INTERRUPT VALID/RESET

R/W

MSB

LSB

DATA1

MSB

LSB

DATA1

MSB

LSB

DATA2

MSB

LSB

DATA4

MSB

LSB

DATA6

MSB

LSB

DATA2

R/W

R/W

INT