Matrix Orbital GLK12232-25, Technical Manual, Page: 17 / 41

Command Summary 17
6 Commands
6.1 Communication
1.1 Change
Baud Rate
Dec
Hex
ASCII 254 57
FE 39
■
9
Speed
Speed
Speed v5.8
Immediately changes the baud rate. Not available in I2C. Baud rate can be temporarily forced to 19200 by a
manual override.
Speed Byte Valid settings shown below.
Table 9: Accepted Baud Rate Values
Rate 9600 14400 19200 28800 38400 57600 76800 115200
Speed 207 138 103 68 51 34 25 16
1.2 Change I2C
Slave Address
Dec
Hex
ASCII 254 51
FE 33
■
3
Address
Address
Address v5.8
Immediately changes the I2C write address. Only even values are permitted as the next odd address will become
the read address. Default is 80.
Address Byte Even value.
1.3 Set a Non-Standard
Baud Rate
Dec
Hex
ASCII 254 164
FE A4
■
ñ
Speed
Speed
Speed v5.0
Immediately changes the baud rate to a non-standard value. Speed must be a whole number between 977 and
153800. Due to rounding, error increases with baud rate, actual baud must be within 3% of desired baud to ensure
accurate communication. Not available in I2C. Can be temporarily forced to 19200 by a manual override.
Speed Short Calculations shown below, standard crystal speed is 16MHz.
𝑆𝑝𝑒𝑒𝑑 =
𝐶𝑟𝑦𝑠𝑡𝑎𝑙𝑆𝑝𝑒𝑒𝑑
(8 × 𝐷𝑒𝑠𝑖𝑟𝑒𝑑𝐵𝑎𝑢𝑑)
− 1
Equation 1: Speed Byte Calculation
𝐴𝑐𝑡𝑢𝑎𝑙𝐵𝑎𝑢𝑑 =
𝐶𝑟𝑦𝑠𝑡𝑎𝑙𝑆𝑝𝑒𝑒𝑑
(8 × (𝑆𝑝𝑒𝑒𝑑 + 1))
Equation 2: Actual Baud Rate Calculation
|𝐷𝑒𝑠𝑖𝑟𝑒𝑑𝐵𝑎𝑢𝑑 − 𝐴𝑐𝑡𝑢𝑎𝑙𝐵𝑎𝑢𝑑|
𝐷𝑒𝑠𝑖𝑟𝑒𝑑𝐵𝑎𝑢𝑑
< 0.03
Equation 3: Baud Rate Error Calculation
1.4 Turn Software
Flow Control On
Dec
Hex
ASCII 254 58
FE 3A
■
:
AlmostFull AlmostEmpty
AlmostFull AlmostEmpty
AlmostFull AlmostEmpty v5.8
Enables simple flow control. The display will return a single, Xoff, byte to the host when the display buffer is
almost full and a different, Xon, byte when the buffer is almost empty. Full value should provide enough room for
the largest data packet to be received without buffer overflow. No data should be sent to the display between full
and empty responses to permit processing. Buffer size is 256* bytes. Not available in I2C. Default off.
AlmostFull Byte Number of bytes remaining before buffer is completely full. Value between 0 and 128.
AlmostEmpty Byte Number of bytes before buffer can be considered empty enough to accept data.