Matrix Orbital VK204-25 Legacy - Manual (Page 22)

Table 3: I 2 C Transaction Algorithm
START Toggle SDA high to low
Address 0x50
Information 0x48 0x45 0x4C 0x4C 0x4F
STOP Toggle SDA low to high
4.1.3 Serial Communication
In addition to being able to communicate via I 2 C the VK204-25 communicates natively through the
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 VK204-25 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.
4.2 Changing the I 2 C Slave Address
Syntax Hexadecimal 0xFE 0x33 [adr]
Decimal 254 51 [adr]
ASCII 254 “3” [adr]
Parameters Parameter Length Description
adr 1 The new I 2 C write address (0x00 -
0xFF).
Description This command sets the I 2 C write address of the module between 0x00
and 0xFF. The I 2 C write address must be an even number and the read
address is automatically set to one higher. For example if the I 2 C write
address is set to 0x50, then the read address is 0x51.
NOTE The change in address is immediate.
Remembered Always
Default 0x50
4.3 Changing the Baud Rate
Syntax Hexadecimal 0xFE 0x39 [speed]
Decimal 254 57 [speed]
ASCII 254 “9” [speed]
Matrix Orbital VK204-25 18