Matrix Orbital DD-DB1 LCD/VFD Dev Board - Manual (Page 30)

6. Keypad
6.1.Auto Transmit
Key Presses On
Dec
Hex
ASCII
254 65
FE 41
A ■
Key presses are automatically sent to the host when received by the display. Default is auto transmit on.
6.2.Auto Transmit
Key Presses Off
Dec
Hex
ASCII
254 79
FE 4F
O ■
Key presses are held in the 10 key buffer to be polled by the host. Use this mode for I 2 C transactions. Default is on.
6.3.Poll Key
Press
Dec
Hex
ASCII 254 38
FE 26
& ■
Reads the last unread key press from the 10 key display buffer. If another key is stored in the buffer the MSB will be 1,
the MSB will be 0 when the last key press is read. If there are no stored key presses a value of 0 will be returned. Auto
transmit key presses must be turned off for this command to be successful.
Response 1 byte, value of key pressed (MSB determines additional keys to be read)
6.4.Clear Key
Buffer
Dec
Hex
ASCII
254 69
FE 45
E ■
Clears all key presses from the display buffer.
6.5.Set
Debounce
Time
Dec
Hex
ASCII 254 85
FE 55
U ■
Time
Time
Time
Sets the time between a key press and a key read by the display. Most switches will bounce when pressed, the debounce
time allows the switch to settle for an accurate read. Default is 8 representing a debounce time of approximately 52ms.
Time 1 byte, debounce increment (debounce time = time * 6.554ms)
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