Datasheet

Device Reset
The reset input RST is an active-low input. When taken
low, RST clears any transaction to or from the MAX7314
on the serial interface and configures the internal regis-
ters to the same state as a power-up reset (Table 3),
which resets all ports as inputs. The MAX7314 then
waits for a START condition on the serial interface.
Detailed Description
Initial Power-Up
On power-up, and whenever the RST input is pulled
low, all control registers are reset and the MAX7314
enters standby mode (Table 3). Power-up status makes
all ports into inputs and disables both the PWM oscilla-
tor and blink functionality. RST can be used as a hard-
ware shutdown input, which effectively turns off any
LED (or other) loads and puts the device into its lowest
power condition.
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).
Ports Configuration
The 16 I/O ports P0 through P15 can be configured to
any combination of inputs and outputs using the ports
configuration registers (Table 5). The INT/O16 output
can also be configured as an extra general-purpose
output, and the BLINK input can be configured as an
extra general-purpose input using the configuration
register (Table 4).
Input Ports
The input ports registers are read only (Table 6). They
reflect the incoming logic levels of the ports, regardless of
whether the port is defined as an input or an output by the
ports configuration registers. Reading an input ports reg-
ister latches the current-input logic level of the affected
eight ports. A write to an input ports register is ignored.
MAX7314
18-Port GPIO with LED Intensity Control,
Interrupt, and Hot-Insertion Protection
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Table 2. Register Address Map
REGISTER
ADDRESS CODE
(hex)
AUTOINCREMENT
ADDRESS
Read input ports P7–P0 0x00 0x01
Read input ports P15–P8 0x01 0x00
Blink phase 0 outputs P7–P0 0x02 0x03
Blink phase 0 outputs P15–P8 0x03 0x02
Ports configuration P7–P0 0x06 0x07
Ports configuration P15–P8 0x07 0x06
Blink phase 1 outputs P7–P0 0x0A 0x0B
Blink phase 1 outputs P15–P8 0x0B 0x0A
Master, O16 intensity 0x0E 0x0E (no change)
Configuration 0x0F 0x0F (no change)
Outputs intensity P1, P0 0x10 0x11
Outputs intensity P3, P2 0x11 0x12
Outputs intensity P5, P4 0x12 0x13
Outputs intensity P7, P6 0x13 0x14
Outputs intensity P9, P8 0x14 0x15
Outputs intensity P11, P10 0x15 0x16
Outputs intensity P13, P12 0x16 0x17
Outputs intensity P15, P14 0x17 0x10