Matrix Orbital GLK24064-25 Legacy - Manual (Page 38)

Description This command shifts the strip chart left or right. [ref] determines both
which strip chart is used and which direction it will shift. The direction
is selected by the most significant bit (MSB):
• MSB: 0 shifts left
• MSB: 1 shifts right
For example if [ref] is 1:
• 254 107 1 (hex FE 6B 01) shifts left
• 254 107 129 (hex FE 6B 81) shifts right
This command shifts the contents of the area defined in the Initialize
Strip Chart command 8 pixels at a time.
Remembered No
9 Keypad
9.1 Introduction
The supports up to a 25 key, matrix style, keypad and may be configured to allow key presses to be
automatically transmitted via RS-232 or polled through I 2 C. The also allows for auto-repeating key presses,
and remapping of all keypad character codes.
The connector is not keyed so the keypad will probably plug in either of two ways. The display will
not be damaged by reversing the connector. However, the keypad will generate a different ASCII character
mapping for each position. If the connector has fewer than 10 pins it should be centered on the display
connector. The keypad is scanned whenever a key is pressed;there is no continuous key scan. This means
that key presses are dealt with immediately without any appreciable latency. This also prevents electrical
noise which is often caused by continuous key scans.
9.1.1 I 2 C Interface
The keypad is read by I 2 C master read. In short, this means that a read of the module will always return
the first unread key press. A read is initiated by writing to the module with its base address plus 1, then
clocking the module’s return byte after the module releases the SDA line. Much more detail on this basic
I
2 C function can be found in the I 2 C specification by Phillips.
9.1.2 RS232 Interface
By default on any press of a key, the module will immediately send out the key code at the selected baud
rate. This behavior can be modified using commands found in the next section.
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