MAX7314 View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

MAX7314

18-Port GPIO with LED Intensity Control, Interrupt, and Hot-Insertion Protection

Maxim Integrated 

18-Port GPIO with LED Intensity Control,

Interrupt, and Hot-Insertion Protection

Table 8. Blink Phase 0 Registers

REGISTER

Write outputs P7–P0 phase 0

Read back outputs P7–P0 phase 0

Write outputs P15–P8 phase 0

Read back outputs P15–P8 phase 0

ADDRESS

R/W CODE

REGISTER DATA

(hex)

D7

D6

D5

D4

D3

D2

D1

D0

0

0x02

OP7 OP6 OP5 OP4 OP3 OP2 OP1 OP0

1

0

0x03 OP15 OP14 OP13 OP12 OP11 OP10 OP9 OP8

1

Table 9. Blink Phase 1 Registers

REGISTER

Write outputs P7–P0 phase 1

Read back outputs P7–P0 phase 1

Write outputs P15–P8 phase 1

Read back outputs P15–P8 phase 1

ADDRESS

R/W CODE

REGISTER DATA

(hex)

D7

D6

D5

D4

D3

D2

D1

D0

0

0x0A

OP7 OP6 OP5 OP4 OP3 OP2 OP1 OP0

1

0

0x0B OP15 OP14 OP13 OP12 OP11 OP10 OP9 OP8

1

Each output’s individual 4-bit intensity control only

operates during the number of timeslots gated by the

master intensity. The individual controls provide 16

intensity settings from 1/16 through 16/16 (Table 14).

Figures 16, 17, and 18 show examples of individual

intensity control settings. The highest value an individ-

ual or global setting can be set to is 16/16. This setting

forces the output to ignore the master control, and fol-

low the logic level set by the appropriate blink phase

register bit. The output becomes a glitch-free static out-

put with no PWM.

Using PWM Intensity Controls with Blink Disabled

When blink is disabled (Table 7), the blink phase 0 reg-

isters specify each output’s logic level during the PWM

on-time (Table 8). The effect of setting an output’s blink

phase 0 register bit to zero or 1 is shown in Table 11.

With its output bit set to zero, an LED can be controlled

with 16 intensity settings from 1/16th duty through fully

on, but cannot be turned fully off using the PWM inten-

sity control. With its output bit set to 1, an LED can be

controlled with 16 intensity settings from fully off

through 15/16th duty.

Using PWM Intensity Controls with Blink Enabled

When blink is enabled (Table 7), the blink phase 0 regis-

ters and blink phase 1 registers specify each output’s

logic level during the PWM on-time during the respective

blink phases (Tables 8 and 9). The effect of setting an

output’s blink phase x register bit to zero or 1 is shown in

Table 12. LEDs can be flipped between either directly on

and off, or between a variety of high/low PWM intensities.

Global/O16 Intensity Control

The 4 bits used for output O16’s PWM individual inten-

sity setting also double as the global intensity control

(Table 13). Global intensity simplifies the PWM settings

when the application requires them all to be the same,

such as for backlight applications, by replacing the 17

individual settings with 1 setting. Global intensity is

enabled with the global intensity flag G in the configura-

tion register (Table 4). When global PWM control is

used, the 4 bits of master intensity and 4 bits of global

intensity effectively combine to provide an 8-bit, 240-

step intensity control applying to all outputs.

It is not possible to apply global PWM control to a sub-

set of the ports, and use the others as logic outputs. To

mix static logic outputs and PWM outputs, individual

PWM control must be selected (Table 10).

16 ______________________________________________________________________________________

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