UR5HCFJL Datasheet, PDF (3/20 Pages) Semtech Corporation – Zero-PowerTM Keyboard Encoder for Portable Systems

FUNCTIONAL DESCRIPTION
The GreenCoder^TM 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.
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
µS 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.
PIN DEFINITIONS
Mnemonic DIP PLCC QFP Type Name and Function
VCC
40 44
38
I Power Supply: +5V
VSS
20 22
17
I Ground
OSCI
39 43
37
I Oscillator input
OSCO
38 42
36
O Oscillator output
_RESET
1
1
41
I Reset: apply 0V to provide orderly start-up
EKC1
37 41
35
I External Keyboard Clock 1:connects
to external keyboard clock line and is used
to generate an interrupt for every clock line
transmission
VX
3
4
43
I Tie to Vcc
OPT
6
7
2
I Used for options selection
KC
8
9
4 I/O Keyboard Clock: connects to PC
keyboard port data line
KD
7
8
3 I/O Keyboard Data: connects to
PC port data line
EKD
10 11
6 I/O External Keyboard Data: connect to
external keyboard clock line
EXC
9 10
5 I/O External Keyboard Clock 1: connects
to external keyboard data line
DRV
2
2
42
I Wake-up line: used for sleep mode
R0-R5
29-34 32-37 27-32
I Row Data Inputs
R6
5
6
1
I
R7
36 39
34
I
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
O columns
C8-C15
28-21 31-24 26-18
O
CL
11 12
7
O Caps Lock LED
NL
4
5
44
O Num Lock LED
SL
35 38
33
O Scroll Lock LED
NC
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.
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.
Copyright Semtech, 1997-2001
3
DOC5-FJL-DS-106
www.semtech.com