LK202-25-USB-WB Matrix Orbital, LK202-25-USB-WB Datasheet - Page 18

• Manufacturer Part Number: LK202-25-USB-WB
• Description: LCD Character Display Modules Blue Background White Text
• Manufacturer: Matrix Orbital
• Series: LK202-25r

Specifications of LK202-25-USB-WB

• Character Count X Line: 20 x 2
• Module Size (w X H X T): 116 mm x 37 mm x 25.73 mm
• Fluid Type: STN
• Voltage Rating: 5 V
• Operating Temperature Range: 0 C to + 50 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

NAK to indicate that the transmission is over.
considerations when writing I
sent (only needs to be sent once, so this can be done somewhere in init): 254 / 160 / 0 this command puts
the reply data in the I
output buffer, query commands that reply with more than 16 bytes cannot be read (eg cmd Get FileSystem
Directory)
4.1.2 I
sequence. To begin a transaction the data line, SDA, must toggle from high to low while the clock line, SCL,
is high. Next, the display must be addressed using a one byte hexadecimal value, the default to write to the
unit is 0x50, while read is 0x51. Then information can be sent to the unit; even when reading, a command
must first be sent to let the unit know what type of information it is required to return. After each bit is sent,
the display will issue an ACK or NACK as described above. Finally, when communication is complete, the
transaction is ended by toggling the data line from low to high while the clock line is high. An example of
the use of this algorithm to write a simple “HELLO” message can be seen in 3.
4.1.3 Serial Communication
RS-232 protocol at at a default baud rate of 19,200 bps and is capable of standard baud rates from 9600 to
115,200 bps. Furthermore the LK202-25-USB is also capable of reproducing any non-standard baud rate in
between using values entered into our baud rate generation algorithm and set through command 164 (0xA4).
The display module communicates at standard voltage levels of -30V to +30V or at TTL levels of 0 to +5V
by setting the Protocol Select Jumpers to TTL.
Matrix Orbital
The LK202-25-USB has some speed limitations, especially when run in I
* to be able to read the replies of query commands (eg. cmds 54, 55) the following command must be
* 3ms delay between the read commands
* 625us delay in between data bytes within a transaction is necessary
* 375us between transactions is necessary
The typical I
In addition to being able to communicate via I
NOTE These delays are consrevative, and may be decreased based on performance
2
C Transaction Example
2
C transaction contains four parts: the start sequence, addressing, information, and stop
2
C output buffer instead of the RS232 output buffer. Please note that due to a 16 byte
2
C code:
Information
Address
START
STOP
Table 3: I
2
LK202-25-USB
C Transaction Algorithm
0x48 0x45 0x4C 0x4C 0x4F
2
Toggle SDA high to low
Toggle SDA low to high
C the LK202-25-USB communicates natively through the
0x50
2
C mode. Here are some
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