All standard characters a-z, A-Z, 0-9 are displayable, as well as all punctuation marks and many other miscellaneous symbols. Byte values between 0×20 and 0×7F will result in the standard ASCII-encoded character. Additionally, byte values between 0xA1 and 0xFF will result in a range of special characters including greek characters, mathematic symbols, and accented letters. For a full list of these characters consult the table at the end of the GDM1602K datasheet.
A carriage return (ENTER), ASCII 0×0D, will advance the cursor to the next row. If it’s on the bottom row, it’ll move to the top.
A line feed (CTRL+ENTER), ASCII 0×0A, will move the cursor to the beginning of the following row. If it’s on the bottom row, it’ll move to the beginning of the top.
A tab, ASCII 0×09, will advance the cursor 5 places.
The backspace character, ASCII 0×08, will operate as a standard backspace: moving the cursor back one digit, and deleting the character there.
The baud rate defaults to 9600bps. To set the baud rate to a different value, send the baud rate control byte (0×81) followed by a second data byte.
The data byte will control the baud rate as according to the following table:
>10: No change
Once the data byte is received the baud rate will be changed. The baud rate is stored in EEPROM, so upon power off and on the baud rate setting will be retained.
To access the special commands send the special command byte (0xFE) followed by the desired data byte. The data bytes are as follows:
Note: You’ll notice the 0×0C command is used in three different instances. The result of this command will depend on which state the display is in. If the display is off, 0×0C will turn it on, but will have no effect on the cursor. If the display is on, and the underline cursor is on, 0×0C will turn that cursor off. Likewise for the blinking box cursor. If the display is not in any one of those states, the 0×0C command will have no effect.