MAX7301AAI-T Maxim Integrated, MAX7301AAI-T Datasheet - Page 5

• Manufacturer Part Number: MAX7301AAI-T
• Description: Interface - I/O Expanders 2.5-5.5V 20/28 Port I/O Expander
• Manufacturer: Maxim Integrated
• Series: MAX7301r

Specifications of MAX7301AAI-T

• Maximum Operating Frequency: 26 MHz
• Operating Supply Voltage: 2.5 V to 5.5 V
• Operating Temperature Range: - 40 C to + 125 C
• Mounting Style: SMD/SMT
• Package / Case: SSOP-28
• Output Current: 4.5 mA, 18 mA

The MAX7301 GPIO peripheral provides up to 28 I/O
ports, P4 to P31, controlled through an SPI-compatible
serial interface. The ports can be configured to any
combination of logic inputs and logic outputs, and
default to logic inputs on power-up.
Figure 1 is the MAX7301 functional diagram. Any I/O
port can be configured as a push-pull output (sinking
10mA, sourcing 4.5mA), or a Schmitt-trigger logic
input. Each input has an individually selectable internal
pullup resistor. Additionally, transition detection allows
seven ports (P24 through P30) to be monitored in any
maskable combination for changes in their logic status.
A detected transition is flagged through an interrupt pin
(port P31).
The port configuration registers set the 28 ports, P4 to
P31, individually as GPIO. A pair of bits in registers
0x09 through 0x0F sets each port’s configuration
(Tables 1 and 2).
The 36-pin MAX7301AAX and 40-pin MAX7301ATL
have 28 ports, P4 to P31. The 28-pin MAX7301AAI is
offered in 20 ports, P12 to P31. The eight unused ports
should be configured as outputs on power-up by writ-
ing 0x55 to registers 0x09 and 0x0A. If this is not done,
the eight unused ports remain as floating inputs and
36 SSOP
5–32
2, 3
33
34
35
36
—
—
—
1
4
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28 SSOP
5–24
2, 3
PIN
—
—
25
26
27
28
—
1
4
_______________________________________________________________________________________
Detailed Description
11, 20, 31
37, 38, 39
12–19,
TQFN
21–30
1–10,
PAD
36
40
32
33
34
35
—
P12–P31
Exposed
P4–P31
NAME
DOUT
SCLK
GND
ISET
N.C.
Pad
DIN
CS
V+
Bias Current Setting. Connect I
39kΩ to 120kΩ.
Ground
4-Wire Interface Serial Data Output Port
I/O Ports. P12 to P31 can be configured as push-pull outputs, CMOS logic
inputs, or CMOS logic inputs with weak pullup resistor.
I/O Ports. P4 to P31 can be configured as push-pull outputs, CMOS logic
inputs, or CMOS logic inputs with weak pullup resistor.
No Connection. Not internally connected.
4-Wire Interface Serial Clock Input Port
4-Wire Interface Serial Data Input Port
4-Wire Interface Chip-Select Input, Active Low
Positive Supply Voltage. Bypass V+ to GND with a minimum 0.047µF
Exposed Pad on Package Underside. Connect to GND.
quiescent supply current rises, although there is no
damage to the part.
The MAX7301 offers 20 or 28 I/O ports, depending on
package choice.
Two addressing methods are available. Any single port
(bit) can be written (set/cleared) at once; or, any
sequence of eight ports can be written (set/cleared) in
any combination at once. There are no boundaries; it is
equally acceptable to write P0 through P7, P1 through
P8, or P31 through P38 (P32 through P38 are nonexis-
tent, so the instructions to these bits are ignored).
When the MAX7301 is in shutdown mode, all ports are
forced to inputs (which can be read), and the pullup
current sources are turned off. Data in the port and
control registers remain unaltered so port configuration
and output levels are restored when the MAX7301 is
taken out of shutdown. The display driver can still be
programmed while in shutdown mode. For minimum
supply current in shutdown mode, logic inputs should
be at GND or V+ potential. Shutdown mode is exited by
setting the S bit in the configuration register (Table 6).
28-Port I/O Expander
SET
FUNCTION
to GND through a resistor (R
Register Control of I/O Ports
Across Multiple Drivers
Pin Description
ISET
Shutdown
) value of
5