Matrix Orbital PK162-12 - Manual (Page 24)

This command sets the time between key press and key read. All key types with the exception of latched
piezo switches will ’bounce’ for a varying time, depending on their physical characteristics. The default
debounce time for the module is about 52 mS, which is adequate for most membrane keypads.
4.5.8 GPO or Keypad Mode (254 37 [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.
5 Bar Graphs and Special Characters
The display includes the ability to draw bar graphs (either horizontal or vertical) and allows users to
define up to eight special characters. Eight characters (ASCII values 0x00 to 0x07) are set aside for use
with bar graphs, user defined characters, and big numbers. Since the same 8 characters are used for each
function, the functions may not be used simultaneously. The characters may be defined or redefined at any
time by issuing the commands shown in this section. Once defined, they may be used either by means of the
bar graph commands, or by simply issuing one of the ASCII values 0x00 to 0x07, which is not prefixed by
the command byte, 254.
5.1 Command List
This chapter describes various graphic commands.
5.1.1 Initialize Wide Vertical Bar Graph (254 118)
This command defines the 8 special / user characters to be blocks suitable for use in drawing wide (5
pixel) vertical bar graphs. Any previously existing definitions will be lost. Once this command has been
issued, any number of vertical bar graphs may be drawn unless the characters are redefined by another
command.
5.1.2 Initialize Narrow Vertical Bar Graph (254 115)
This command defines the 8 special / user characters to be blocks suitable for use in drawing narrow (2
pixel) vertical bar graphs. Any previously existing definitions will be lost. Once this command has been
issued, any number of vertical bar graphs may be drawn unless the characters are redefined by another
command.
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