ISSI IS31IO7326 User Manual

IS31IO7326 Debounced 8x8 Key-Scan Controller Evaluation Board Guide

Description

IS31IO7326 is a 64 key, key-scan controller. It offloads
the burden of keyboard scanning from the host
processor. The IS31IO7326 supports keypad matrix of
up to 8×8. Key press and release events are encoded
into a byte format and loaded into a key event register
for retrieval by the host processor.

To minimize power, the IS31IO7326 automatically
enters a low power standby mode when there is no
keypad, I/O, or host activity.

Features

• Supply voltage range from 3.0V to 5.5V

• 400kHz I2C serial interface

• Available for multi-key press detect

• Low 0.3µA (typ.) standby current

• Operate in -40°C to +125°C

• Pb-free 4mm × 4mm QFN-24 package

Quick Start

Recommended Equipment

• 5.0V, 2A power supply

Absolute Maximum Ratings

• ≤ 5.5V power supply

Caution: Do not exceed the conditions listed above, otherwise
the board will be damaged.

Procedure

The IS31FL7326 evaluation board is fully assembled
and tested. Follow the steps listed below to verify
board operation.

Caution: Do not turn on the power supply until all connections
are completed.

1) Connect the ground terminal of the power supply
to the GND and the positive terminal to the VCC.
Or connect the DC power to the connector (DC
IN).

2) Turn on the power supply and pay attention to the
supply current. If the current exceeds 200mA,
please check for circuit fault.

Figure 1: Photo of IS31IO7326 Evaluation Board

Evaluation Board Ordering Information

Part No. IC Package

IS31IO7326-QFLS4-EB QFN-24, Lead-free

Table1: Ordering Information

For pricing, delivery, and ordering information, please contacts ISSI’s analog marketing
team at [e-mail] or [phone].

Integrated Silicon Solution, Inc. – www.issi.com

R1.0, 08/23/2012

1

IS31IO7326 Debounced 8x8 Key-Scan Controller Evaluation Board Guide

Evaluation Board Operation

K0 to K63 are push buttons on the demo
board. When each of the button is pressed
briefly, a number corresponding to the key will
be displayed. When the button is pressed
and held for a few seconds, the period dot will
also be displayed. If two buttons are
pressed at the same time, the corresponding
key numbers will be displayed.

Note:

IS31IO7326 solely controls the Key-Scan function on the
evaluation board.

PP0

PP1

PP2

PP3

PP4

PP5

PP6

PP7

3V

R4

4.7K

SCL
SDA
INT
RST

Integrated Silicon Solution, Inc. – www.issi.com

R1.0, 08/23/2012

VCC

R5

K0 K8 K16 K24 K32

100K

K1 K9 K17 K25 K33 K41 K49 K57

K2 K10 K18 K26 K34 K42 K50 K58

K3 K11 K19 K27 K35 K43 K51 K59

K4 K12 K20 K28 K36 K44 K52 K60

K5 K13 K21 K29 K37 K45 K53 K61

K6 K14 K22 K30 K38 K46 K54 K62

K7 K15 K23 K31 K39 K47 K55 K63

OD0 OD1 OD2 OD3 OD4 OD5 OD6 OD7

U1

VCC

21

VCC

C2
1uF

R1

R2

4.7K

4.7K

19

SCL

20

SDA

22

INT

23

RST

R3
100K

18

AD0

24

AD1

9

GND

IS31IO7326

R6
100K

R7
100K

1

PP0

2

PP1

3

PP2

4

PP3

14

PP4

15

PP5

16

PP6

17

PP7

5

OD0

6

OD1

7

OD2

8

OD3

10

OD4

11

OD5

12

OD6

13

OD7

R8
100K

PP0
PP1
PP2
PP3

JP1

PP4

OPEN=EXT CTRL

PP5
PP6
PP7
OD0
OD1
OD2
OD3
OD4
OD5
OD6
OD7

TP3

R9
100K

U3

1

20
19
18
14
10

8
3
2

LPC922

GND

5

RST

4

SDA

3

SCL

2

INT

1

P0.0/CMP2/KBI0

P0.1/CIN2B/KBI1
P0.2/CIN2A/KBI2
P0.3/CIN1B/KBI3
P0.6/CMP1/KBI6
P1.2/T0/SCL
P1.4/INT1
P1.6
P1.7

Figure 2:IS31IO7326 Application Schematic

2

Software support

Note:
JP1 is set to close circuit by default. If it is set to open, the

on-board MCU will stop working. The pins driving the I2C pin
from MCU will be set to High Impedance. External control
signals can be connected to TP3 port to control the IS31IO7326.

Refer to the datasheet to get more information about
IS31IO7326.

U4

VCC

11

R10

K40 K48 K56

100K

P0.4/CIN1A/KBI4

P0.5/CMPREF/KBI5

P0.7/T1/KBI7

P1.3/INT0/SDA

P3.1/XTAL1

P3.0XTAL2/CLKOUT

TP4

5
4
3
2
1

P1.0/TXD
P1.1/RXD

P1.5/RST

3V
P0.5
P0.4
RESET
GND

VDD

R11
100K

3V

15

17

P0.4

16

P0.5

13

RST

12

SDA

11

SCL

9

INT

4

RESET

6
7

5

VSS

CON1
DC IN

R12
100K

TP1

10uFC11uF

TP2

VDD

3

SDB

C3
1uF

SDA

1

SDA

SCL

2

SCL

4

IN

5

C_FILT

6

AD

20

GND

IS31FL3728

DIG1

H3

H2

H1

12

C4

8

9

U2

1

VDD

3

SD

2

GND

PAM3101

VOUT

C1
C2
C3
C4
C5
C6
C7
C8

R8/C9
R7/C10
R6/C11

R5
R4
R3
R2
R1

DP

g
f
e
d
c
b
a

H4
6

C1C2C3C4

3VVCC

5

C5
10nF

4

BP

24

C1

23

C2

22

C3

21

C4

19
18
17
16
15

DP

14

g

13

f

12

e

10

d

9

c

8

b

7

a

3

DP

5

g

10

f

1

e

2

d

4

c

7

b

11

a

C6
1uF

IS31IO7326 Debounced 8x8 Key-Scan Controller Evaluation Board Guide

Bill of Materials

Name Symbol Description Qty Supplier Part No.

I/O IC U1 16 I/O ports.Expander 1 ISSI IS31IO7326

LDO U2 Low-dropout Regulator 1 PAM PAM3101

MCU U3 Microcontroller 1 NXP LPC922

LED Driver U4 Array FxLED Driver 1 ISSI IS31FL3728

Displayer DIG1
Resistors R1,R2,R4 RES,4.7k,1/16W,±5%,SMD 3

Resistor R3 RES,100k,1/16W,±5%,SMD 1
Resistors R5~R12 RES,100k,1/16W,±5%,SMD 8
Capacitor C1 CAP,10µF,16V,±20%,SMD 1

Capacitors C2,C3,C4,C6 CAP, 1µF,16V,±20%,SMD 4

Capacitor C5 CAP,10nF,16V,±20%,SMD 1

4 Digit Display, Common
Kathode

1 ZSO 3461AS

Buttons K0~K63 Button SMD 64

Table 2: Bill of Materials, refer to Figure 2 above.

Integrated Silicon Solution, Inc. – www.issi.com

R1.0, 08/23/2012

3

IS31IO7326 Debounced 8x8 Key-Scan Controller Evaluation Board Guide

10

11

2

1

0

2

2

2

1

2

000000

43

2

5

6

7

8

9

10

000000

21

20

19

18

22

1312

11

10

11 12

17

9

13

14

1516

14

12

00

1

2

3

4

5

1

2

0

Figure 3: Board Component Placement Guide -Top Layer

Figure 4: Board PCB Layout- Top Layer

Integrated Silicon Solution, Inc. – www.issi.com

R1.0, 08/23/2012

4

IS31IO7326 Debounced 8x8 Key-Scan Controller Evaluation Board Guide

10

11

2

1

0

2

2

2

1

2

000000

43

2

5

6

7

8

9

10

000000

21

20

19

18

22

1312

11

10 11 12

17

9

13

14

1516

14

12

00

1

2

3

4

5

1

2

0

Figure 5: Board Component Placement Guide -Bottom Layer

Figure 6: Board PCB Layout-Bottom Layer

Integrated Silicon Solution, Inc. – www.issi.com

R1.0, 08/23/2012

5

IS31IO7326 Debounced 8x8 Key-Scan Controller Evaluation Board Guide

Copyright © 201

2 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification

and its products at any time without notice. ISSI assumes no liability arising out of the application or use of any information,
products or services described herein. Customers are advised to obtain the latest version of this device specification before relying
on any published information and before placing orders for products.
Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or
malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety
or effectiveness. Products are not authorized for use in such applications unless Integrated Silicon Solution, Inc. receives written
assurance to its satisfaction, that:
a.) the risk of injury or damage has been minimized;
b.) the user assume all such risks; and
c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances

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R1.0, 08/23/2012