MAX7316 Maxim, MAX7316 Datasheet - Page 14

• Manufacturer Part Number: MAX7316
• Description: The MAX7316 I²C/SMBus™-compatible serial interfaced peripheral provides microprocessors with eight additional I/O ports plus one output-only port and one input-only port
• Manufacturer: Maxim

The blink mode is disabled by clearing the blink enable
flag E in the configuration register (Table 4). When blink
mode is disabled, the state of the blink flip flag is
ignored, and the blink phase 0 register alone controls
the output ports.
The logic status of BLINK is made available as the
read-only blink status flag, blink in the configuration
register (Table 4). This flag allows BLINK to be used as
an extra general-purpose input (GPI) in applications not
using the blink function. When BLINK is going to be
used as a GPI, blink mode should be disabled by
clearing the blink enable flag E in the configuration reg-
ister (Table 4).
When the blink function is disabled, the blink phase 0
register sets the logic levels of the eight ports (P0
through P7) when configured as outputs (Table 8). A
duplicate register called the blink phase 1 register is
also used if the blink function is enabled (Table 9). A
logic high sets the appropriate output port high imped-
ance, while a logic low makes the port go low.
10-Port I/O Expander with LED Intensity
Control, Interrupt, and Hot-Insertion Protection
Table 4. Configuration Register (continued)
X = Don’t care.
14
output is low when interrupt enable (I bit)
Read back data change interrupt status
Read back data change interrupt status
—data change is detected, and INT/O8
Read back BLINK input pin status—
Read back BLINK input pin status—
INT/O8 output is high when interrupt
—data change is not detected, and
______________________________________________________________________________________
CONFIGURATION
enable (I bit) is set
input is high
REGISTER
input is low
is set
Blink Phase Register
R/W
1
1
1
1
ADDRESS
CODE
(HEX)
0x0F
D7
X
X
0
1
Reading a blink phase register reads the value stored
in the register, not the actual port condition. The port
output itself may or may not be at a valid logic level,
depending on the external load connected.
The 9th output, O8, is controlled through 2 bits in the
configuration register, which provide the same static or
blink control as the other eight output ports.
The MAX7316 includes an internal oscillator, nominally
32kHz, to generate PWM timing for LED intensity con-
trol or other applications such as PWM trim DACs.
PWM can be disabled entirely for all the outputs. In this
case, all outputs are static and the MAX7316 operating
current is lowest because the internal PWM oscillator is
turned off.
Figure 11. Blink Logic
D6
BLINK ENABLE FLAG E
X
X
0
1
BLINK FLIP FLAG B
BLINK INPUT
D5
X
X
X
X
REGISTER DATA
D4
X
X
X
X
PWM Intensity Control
D3
X
X
X
X
D2
X
X
X
X
BLINK
PHASE
REGISTERS
D1
X
X
X
X
D0
X
X
X
X