GreenCoder

UR5HCFJL

Zero-Power

Keyboard

Encoder for Portable Systems

GreenCoder is a trademark of Semtech Corp. All
other trademarks belong to their respective
companies.

www.semtech.com

HID & SYSTEM MANAGEMENT PRODUCTS, KEYCODER

FAMILY

DESCRIPTION

FEATURES

The GreenCoder

(UR5HCFJL) is

a unique, Zero-Power

keyboard

encoder that provides an optimum
performance level for both battery-
operated and desktop systems.

The GreenCoder

scans,

debounces and encodes an 8 X 16
keyboard matrix, and will provide
direct drive for 3 LEDs and two
bi-directional channels for
communication with a BIOS-
compatible system as well as an
additional keyboard-compatible
device. It fully supports all three
PS/2 scan code sets and will
implement up to three alternate
keyboard layers for full 101/102
functionality.

The GreenCoder

employs a

unique Self-Power Management

method that reduces the power
consumption of the keyboard
sub-system to an unprecedented
minimum, transparently and without
user intervention. In "Active" mode,
the encoder consumes less than 2
mA (Typ @5V). In "Sleep" mode the
encoder consumes less than 2 礎
(Typ @5V) The encoder can even
nap between keystrokes and
therefore it is rarely active and
rarely consumes significant levels of
power.

A "stand-by" mode (600 礎 Typ

@5V) is entered for as long as
a periodic task is active. After a
programmed period of user
inactivity the GreenCoder

gradually dims the LEDs for
further power savings.

The GreenCoder

is ideal for use in

battery laptop/notebook designs
and Energy Star compliant
keyboards.

DRV

_RESET

VCC

OSCI

OSCO

EKC1

OPT

KD
KC

EKC
EKD

CL
C0
C1
C2
C3
C4

R7
SL
R5
R4
R3
R2
R1
R0
C8
C9
C10

GND

C15

C14

C13

C12

C11

PLCC

_RESET

DRV

OPT

EKC

EKD

GND

VCC

OSCI

OSCO

EKC1

C10

C11

C12

C13

C14

C15

DIP

OPT

EKC

EKD

DRV

_RESET

VCC

OSCI

OSCO

EKC1

C10

C11

GND

C15

C14

C13

C12

QFP

� Laptop/Notebook
� Portable Equipment

� Energy Star Compliant
� Medical Instruments
� Palmtops/ PDAs

� Wakes-up only to respond to an

external event and for a minimum
period of time (2 mA current
consumption)

� Provides interface for external

keyboard/keypad or other 8042-
compatible device

� Custom versions available in small

or large quantities

� Optimized power-saving operation

with idle consumption of less
than 2 礎

� Programmable LED dimming for

further power savings

� Ready to interface to Fujitsu's

7316, 7654,7656, and
1406 keyboards

� 3, 3.3 and 5 Volt operation

APPLICATIONS

PIN ASSIGNMENTS

FUNCTIONAL DIAGRAM

ORDERING CODE

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XX = 16 for FKB7136,06 for FKB1406 matrix compatibility

Data Buffer

Interrupt Control

Communication

Channel

8042 Emulation

(External Keyboard)

Communication

Channel

EKC1

EKC

EKD

Keyboard Encoder

Mode Control

Status LEDs

Row Data Inputs

Column Select

Ouputs

NL/CL/SL

DRV

16-Bit Timer

C0-C15

R0-R7

Package options
40-pin Plastic DIP
44-pin, Plastic PLCC
44-pin, Plastic QFP

Pitch In mm's
2 54 mm
1.27 mm
0.8 mm

TA = -40癈 to +85癈
UR5HCFJL-XX-P
UR5HCFJL-XX-FN
UR5HCFJL-XX-FB

FUNCTIONAL DESCRIPTION

PIN DEFINITIONS

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The GreenCoder

consists

functionally of seven major sections
(see Functional Diagram, previous
page). These are the Keyboard
Encoder, a 16-Bit Timer, the Mode
Control Unit, the Data Buffer, the
Interrupt Control, the PC Commun-
ication Channel and the 8042
Emulation Channel. All sections
communicate with each other and
operate concurrently.

Mnemonic DIP

PLCC

QFP

Type

Name and Function

VCC

Power Supply: +5V

VSS

Ground

OSCI

Oscillator input

OSCO

Oscillator output

_RESET

Reset: apply 0V to provide orderly start-up

EKC1

External Keyboard Clock 1:connects
to external keyboard clock line and is used
to generate an interrupt for every clock line
transmission

Tie to Vcc

OPT

Used for options selection

I/O

Keyboard Clock: connects to PC
keyboard port data line

I/O

Keyboard Data: connects to
PC port data line

EKD

I/O

External Keyboard Data: connect to
external keyboard clock line

EXC

I/O

External Keyboard Clock 1: connects

to external keyboard data line

DRV

Wake-up line: used for sleep mode

R0-R5

29-34

32-37

27-32

Row Data Inputs

C0-C4

12-16

13-17

8-12

I/O

Column Select Outputs: select 1 of 16

C5-C7

17-19

19-21

13-15

columns

C8-C15

28-21

31-24

26-18

Caps Lock LED

Num Lock LED

Scroll Lock LED

3,18

39-40

No Connects: these pins are unused

23,40

16,22

Note: An underscore before a pin mnemonic denotes an active low signal.

KEYBOARD ENCODER

The encoder scans a keyboard
organized as an 8 row by 16 column
matrix for a maximum of 128 keys.
Smaller-size keyboards are support-
ed provided that all unused row
lines are pulled to Vcc. When
active, the encoder selects 1 of the
16 column lines (C0-C15) every 512
礢 and then reads the row data
lines (R0-R7). A key closure is
detected as a 0 in the
corresponding position of the matrix.
A complete scan cycle for the entire
keyboard takes approximately 9.2
mS. Each key found pressed is
debounced for a period of 20 mS.
Once the key is verified, the
corresponding key code(s) are
loaded into the transmit buffer of the
PC keyboard communication
channel.

Scan Code Table Sets

The UR5HCFJL supports all three
scan code table sets. Scan Code
Table Set 3 allows the user to
program individual key attributes
such as Make/Break and Typematic
or Single-Touch Action. For more
information, refer to the IBM Tech-
nical Reference Manuals. Custom
scan code tables, including macros,
are also available.

KEYBOARD ENCODER, (CON'T)

MODE CONTROL

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Embedded Numeric Keypad

The GreenCoder

implements an

embedded numeric keypad. The
Numeric Keypad Function is
invoked by pressing the Num Lock
Key.

FN Key

A special FN Key has been
implemented to perform the
following functions while it is held
pressed:

� Function Key F1 becomes F11

� Function Key F2 becomes F12

� Control Left Key becomes Ctrl
Right

� Embedded numeric keypad keys
become regular keys

If Num Lock is not set:

� Embedded numeric keypad keys
provide the same codes as a
numeric keypad when the Num
Lock is not set (Arrow keys, PgUp,
PgDn, etc.)

Status LED indicators

The controller provides an interface
for three LED shift status indicators.
All three pins are active low to
indicate the status of the host
system (Num Lock, Caps Lock and
Scroll Lock) and are set by the
system. After approximately a one-
minute period of keyboard inactivity,
LEDs are dimmed to conserve
power. They are set to full
brightness again upon a new
keystroke.

N-Key Rollover

In this mode, the code(s) corresponding to each key press are transmitted
to the host system as soon as that key is debounced, independently of the
release of other keys.

If a key is defined to be Typematic, the corresponding make code(s) will be
transmitted while the key is held pressed. When a key is released, the
corresponding break code(s) are then transmitted to the host system. If the
released key happens to be the most recently pressed, then Typematic
action is terminated. There is no limitation in the number of keys that can
be held pressed at the same time. However, two or more key closures,
occurring within a time interval less than 5 mS, will set an error flag and will
not be processed. This procedure protects against effects of accidental key
presses.

"Ghost" Keys

In any scanned contact switch matrix, whenever three keys defining a
rectangle on the switch matrix are held pressed at the same time, a fourth
key positioned on the fourth corner of the rectangle is sensed as being
pressed. This is known as the "ghost" or "phantom" key problem. Although
the problem cannot be totally eliminated without using external hardware,
there are methods to neutralize its negative effects for most practical
applications. Keys that are intended to
be used in combinations or are likely to
be pressed at the same time by a fast
typist (i.e., keys located in adjacent
positions on the keyboard) should be
placed in the same row or column of the
matrix whenever possible. Shift Keys
(Shift, Alt, Ctrl) should not reside in the
same row (or column) with any other
keys. The GreenCoder

has built-in

mechanisms to detect the presence of a
"ghost" key, thus eliminating the
necessity of external hardware.

Actual key presses

"Ghost"

Key

Figure 1: "Ghost" or "Phantom" Key
Problem

8042 EMULATION CHANNEL

SPECIAL HANDLING

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The GreenCoder

fully emulates a

system's keyboard port, available to
a standard 84/85/101/102 external
keyboard or other 8042-compatible
device. Communication with a
keyboard-compatible device is
accomplished by clock and data
lines via EKC and EKD pins,
respectively. A third pin, EKC1 that
connects to the Clock Line,
interrupts the controller whenever
the external device initiates a
communication session.

When power is first applied, the
controller proceeds with the
standard reset sequence with the
external device. Data and
commands initiated from the
external device are buffered in the
controller's FIFO along with data
from the scanned matrix, and then
are presented to the system as if
they were coming from a single
source. Once they are
acknowledged, commands and
data from the system are then
transmitted to the external device.

Connection of External Device

The UR5HCFJL will detect the presence of an external device. If an
external keyboard or other device was not connected during power-on and
is connected at a later time, the encoder will proceed with the normal reset
routine in order to properly initialize the external device. After
communication has been established, the encoder will continue to check for
the presence of the external device. While the external device is
connected, the encoder will not enter the sleep mode. If the device is
disconnected at a later time, the encoder will become aware of it. If a
subsequent connection takes place, the controller will re-initiate a reset
sequence. This unique feature allows the user to connect or disconnect an
external device at any time without having to reset the system.

Shift Status LEDs

Shift Status LEDs (Num Lock, Caps Lock and Scroll Lock) indicate the
status of the system and are controlled by commands sent from the system.
Set/Reset Status Indicator Commands from the system will be executed
both by the external keyboard and the scanned matrix.
For example, if the user presses the Caps Lock Key on either keyboard, the
Caps Lock LED will be affected on both keyboards. The LED status
indicators are properly set after each new connection of an external
keyboard.

协谢械泻褌褉芯薪薪褘泄 泻芯屑锌芯薪械薪褌: UR5HCFJL-P

协谢械泻褌褉芯薪薪褘泄泻芯屑锌芯薪械薪褌: UR5HCFJL-P