Datasheet

MAX7306/MAX7307
SMBus/I
2
C Interfaced 4-Port, Level-Translating
GPIOs and LED Drivers
10 ______________________________________________________________________________________
Slave Address
The MAX7307 is set to slave address 0x98 and the
MAX7306 can be set to one of four I
2
C slave addresses
0x98 to 0x9F, using the address input AD0 (see Table 5)
and is accessed over an I
2
C or SMBus serial interface.
The MAX7306 slave address is determined on each I
2
C
transmission, regardless of the transmission actually
addressing the device or not. The MAX7306 distin-
guishes whether address input AD0 is connected to
SDA, SCL, V
DD
, or GND during the transmission.
Therefore, the MAX7306 slave address can be config-
ured dynamically in an application without toggling the
device supply.
I/O Port Registers
The port I/O registers set the I/O ports, one register per
port (see Tables 6 and 7). Use the I/O port registers to
configure the ports individually as inputs, open-drain, or
push-pull outputs. Port P1 can only be configured as an
input or an open-drain output. The push-pull bit (D6) set-
ting for the port I/O register P1 is ignored.
I/O Input Port
Configure a port as an input by writing a logic-high to the
MSB (bit D7) of the port I/O register (see Table 6). To
obtain the logic level of the port input, read the port I/O
register bit, D0. This readback value is the instantaneous
logic level at the time of the read request if debounce is
disabled for the port (port I/O register bit D2 = 0), or the
debounced result if debounce is enabled for the port
(port I/O register bit D2 = 1). See Figure 1 for input port
structure.
I/O Output Port
Configure a port as an output by writing a logic-low to the
MSB (bit D7) of the port I/O register. The device reads
back the logic level, PWM, or the blink setting of the port
(see Table 7).
DEVICE ADDRESS
AD0
C O NN EC TIO N
A6 A5 A4 A3 A2 A1 A0
R /W
GND
1001100
0/1
V
DD
1001101
0/1
SCL
1001110
0/1
SDA
1001111
0/1
Table 5. Slave-Address Selection
REGISTER BIT DESCRIPTION
VALUE
FUNCTION
D7 Port I/O Set Bit 1 Sets the I/O port as an input.
0 Refers the input to the V
LA
supply voltage.
D6*
Port Supply
Reference
1 Refers the input to the V
DD
supply voltage.
0 Disables the transition interrupt.
D5
Transition Interrupt
Enable
1 Enables the transition interrupt.
D4, D3 Reserved 0 Do not write to these registers.
0 Disables debouncing of the input port.
D2 Debounce
1 Enables debouncing of the input port.
0 No transition has occurred since the last port read.
D1
Port Transition
State (Read-Only)
1 A transition has occurred since the last port read.
0 Port input is logic-low.
D0
Port Status
(Read-Only)
1 Port input is logic-high.
Table 6. Port I/O Registers (I/O Port Set as an Input, Registers 0x01 to 0x04)
*Bit D6 controls the I/O’s supply reference for the MAX7307. The MAX7306 ignores bit D6.