PK202-25 Matrix Orbital, PK202-25 Datasheet - Page 24

• Manufacturer Part Number: PK202-25
• Description: LCD Character Display Modules Black Background Yel/Grn Text
• Manufacturer: Matrix Orbital
• Series: PK202-25r

Specifications of PK202-25

• Character Count X Line: 20 x 2
• Module Size (w X H X T): 116 mm x 37 mm x 25.73 mm
• Background Color: Black
• Backlight Type: LED Yellow / Green
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.3 I
first unread key press. A read is initiated by writing to the module with its base address plus 1, then clocking
the module’s return byte after the module releases the SDA line. Much more detail on this basic I
can be found in the I
(every 500 to 1000 ms is typical). All returned key presses indicate the presence or absence of additional
logged key presses by the most significant bit (MSB - bit 7). If the user has pressed two keys since the last
poll of the keypad interface, the first read will return the key code with bit 7 set and the second read will
return the key code with bit 7 clear. The application must take into account this bit to keep up with user key
presses. If there are no keypresses detected, the module will return zero (0x00).
4.4 RS-232 Interface
rate. This behavior can be modified using commands found in the next section.
Matrix Orbital
The keypad can be read by I
A good reference is also available at:
The module contains a ten key press buffer so that it can be polled for key presses at an infrequent rate
By default on any press of a key, the module will immediately send out the key code at the selected baud
NOTE The keypads may be laid out in a different pattern. If this is the case, the user
will need to interpret the key codes differently. Also included are two extra pins on each
end of the connector to be used for ground strapping. This can be used in conjunction with
your keypad if a ground strap connection is required or if a common ground connection is
needed.
NOTE The keypad connector must be wired with columns on one side and rows on the
other side of the center of the connector. In situations where the keypad isn’t wired this
way an adapter will need to be made, or the user should rewire the connector to meet this
requirement.
2
C Interface
2
C specification by Phillips.
2
C master read. This means that a read of the module will always return the
Rows
Table 9: Keypad Layout
1
2
3
4
5
PK202-25
A
K
U
F
P
1
Columns
B
G
Q
V
L
2
W
M
H
C
R
3
D
N
X
4
S
I
O
Y
E
T
5
J
2
C function
20