LCD0821-WB-E Matrix Orbital, LCD0821-WB-E Datasheet - Page 16

• Manufacturer Part Number: LCD0821-WB-E
• Description: LCD ALPHA/NUM DISPL 8X2 BLU WHT
• Manufacturer: Matrix Orbital
• Series: LCD0821r

Specifications of LCD0821-WB-E

• Display Mode: *
• Number Of Digits/alpha: 16
• Display Format: 8 x 2
• Character Format: *
• Interface: I²C, RS232, TTL
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply: -
• Operating Temperature: -
• Display Type: -
• Backlight: -
• Viewing Area: -
• Outline L X W X H: -
• Dot Size: -
• Character Size: -
• Other names: Q3530625

0 for an I
(0101 0001), since the LSB has to be 1 for an I
this Phillips I
When writing to the display module, the display will respond with a ACK when the write has successfully
been completed. However if the buffer has been filled, or the module is too busy processing data it will
respond with a NAK. When performing a multiple byte read within one I
the slave should be followed by an ACK to indicate that the master still needs data, and a NAK to indicate
that the transmission is over.
tions 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.
Matrix Orbital
If we take a standard Phillips 7 bit address of $45 (100 0101), Matrix Orbital’s LCD0821 would describe
The unit does not respond to general call address ($00).
When communicating in I
The LCD0821 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
NOTE These delays are consrevative, and may be decreased based on performance
2
C master write. When the I
2
C Transaction Example
2
C address as $8A (1000 1010). The read address would be $8B (1000 1011).
2
C transaction contains four parts: the start sequence, addressing, information, and stop
2
C code:
2
C output buffer instead of the RS232 output buffer. Please note that due to a 16 byte
2
C the LCD0821 will send an ACK on the 9th clock cycle when addressed.
Information
Address
START
STOP
Table 3: I
2
C master wishes to read the LCD0821, the effective address is $51
2
C Transaction Algorithm
2
0x48 0x45 0x4C 0x4C 0x4F
C master read.
LCD0821
Toggle SDA high to low
Toggle SDA low to high
0x50
2
2
C mode. Here are some considera-
C transaction, each byte read from
12