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Max7315, Detailed description, Command address autoincrementing – Rainbow Electronics MAX7315 User Manual

Page 12: Device reset, Initial power-up, Configuration register

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MAX7315

Command Address Autoincrementing

The command address stored in the MAX7315 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
MAX7316. The MAX7316 includes a RST input, which
clears any transaction to or from the MAX7316 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
MAX7315 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/O8 output, and read back the interrupt status
(Table 4).

8-Port I/O Expander with LED Intensity
Control and Interrupt

12

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Figure 10. Read, Write, and Interrupt Timing Diagrams

SLAVE ADDRESS

1

2

3

4

5

6

7

8

9

S A6 A5 A4 A3 A2 A1 A0

0

A

0

0

0

0

0

0

0

COMMAND BYTE

1

A

A

A

P

START CONDITION

ACKNOWLEDGE FROM SLAVE

ACKNOWLEDGE FROM SLAVE

ACKNOWLEDGE FROM SLAVE

STOP

CONDITION

P7–P0

DATA1 VALID

DATA2 VALID

SLAVE ADDRESS

1

2

3

4

5

6

7

8

9

S A6 A5 A4 A3 A2 A1 A0

1

A

COMMAND BYTE

A

NA

START CONDITION

ACKNOWLEDGE FROM SLAVE

ACKNOWLEDGE FROM MASTER

P7–P0

STOP CONDITION

P

NO ACKNOWLEDGE FROM
MASTER

DATA2

DATA3

t

DV

t

DV

SLAVE ADDRESS

1

2

3

4

5

6

7

8

9

S A6 A5 A4 A3 A2 A1 A0 1

A

COMMAND BYTE

A

NA

START CONDITION

ACKNOWLEDGE FROM SLAVE

ACKNOWLEDGE FROM MASTER

P7–P0

STOP CONDITION

P

NO ACKNOWLEDGE FROM
MASTER

DATA1

DATA2

DATA3

DATA4

t

DH

t

DS

DATA1

t

IV

t

IR

t

IR

t

IV

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

DATA4

MSB

LSB

DATA2

R/W

R/W

INT