Matrix Orbital VK162-12 Legacy - Manual (Page 32)

size of the FIFO. The reason for this is that the FIFO may be full when the host system receives 0xFE. In
the case of 16550 UART the size at its maximum is 16, therefore the value of should be set to 16 or greater.
6.2.2 Exit Flow Control Mode (254 59)
This command turns off flow control. Bytes may overflow the buffer without warning.
6.2.3 GPO or Keypad Mode (254 126 [mode])
The display shares GPO and keypad pins, you can use one of the other but not both at the same time.
To select either general purpose outputs or the keypad interface on the general purpose output / keypad
connector, send a command prefix followed by the character ’%’ followed by , where is either 0 or 1 (8 bit
binary).
0 = Keypad Interface Mode
1 = General Purpose Output Mode.
7 Appendix: Command Summary
7.1 General
The operation of the display is controlled by a simple and consistent command set.
Commands control;
• Text display
• Graphics display
• Keypad interface
• Miscellaneous operating parameters
This chapter includes summary tables of all commands.
7.2 Issuing Commands
Commands are issued to the display by the controller. In a test setup, commands can be issued to
the display by means of a BASIC program, using the chr$( ) function. In the tables below, we’ve shown
commands in hex, ASCII and decimal form. All commands begin with the prefix character 0xFE (254
decimal). These commands are issued on the serial communications link (I 2 C or RS-232) at the currently
defined baud rate.
For example (using BASIC in a test setup), the user could issue the command to clear the screen on the
display by including the line;
ˆ‰UQp£‘¢’U(“s3Q ¢E1”IbP2£'•UeHfs3$ £Eu”SbP‚‚)e
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