MAX7316 View Datasheet(PDF) - Maxim Integrated
Part Name
Description
Manufacturer
MAX7316
Maxim Integrated
MAX7316 Datasheet PDF : 24 Pages
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10-Port I/O Expander with LED Intensity
Control, Interrupt, and Hot-Insertion Protection
Table 8. Blink Phase 0 Register
REGISTER
Write outputs phase 0
Read back outputs 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
Table 9. Blink Phase 1 Register
REGISTER
Write outputs phase 1
Read back outputs 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
Using PWM Intensity Controls with Blink Enabled
When blink is enabled (Table 7), the blink phase 0 regis-
ter and blink phase 1 register 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 0 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/O8 Intensity Control
The 4 bits used for output O8’s PWM individual intensity
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 9 individ-
ual settings with 1 setting. Global intensity is enabled
with the Global Intensity flag G in the configuration reg-
ister (Table 4). When global PWM control is used, the 4
bits of master intensity and 4 bits of O8 intensity effec-
tively 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).
Applications Information
Hot Insertion
I/O ports P0-P7, interrupt output INT/O8, RST input,
BLINK input, and serial interface SDA, SCL, AD0 remain
high impedance with up to 6V asserted on them when
the MAX7316 is powered down (V+ =0V). The MAX7316
can therefore be used in hot-swap applications.
Output Level Translation
The open-drain output architecture allows the ports to
level translate the outputs to higher or lower voltages
than the MAX7316 supply. An external pullup resistor
can be used on any output to convert the high-imped-
ance logic-high condition to a positive voltage level.
The resistor can be connected to any voltage up to
5.5V. For interfacing CMOS inputs, a pullup resistor
value of 220kΩ is a good starting point. Use a lower
resistance to improve noise immunity, in applications
where power consumption is less critical, or where a
faster rise time is needed for a given capacitive load.
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