VK204-25-422-E Matrix Orbital, VK204-25-422-E Datasheet - Page 31

• Manufacturer Part Number: VK204-25-422-E
• Description: VF CHARACTER DISPLAY 20X4 RS422
• Manufacturer: Matrix Orbital
• Series: LK204-25r

Specifications of VK204-25-422-E

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

6. Keypad
6.1. Auto Transmit
Key presses are automatically sent to the host when received by the display. Default is Auto Transmit on.
6.2. Auto Transmit
Key presses are held in the 10 key buffer to be polled by the host using the Poll Key Press command. Use this
mode for I2C transactions. Default is Auto Transmit on.
6.3. Poll Key
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
6.4. Clear Key
Clears all key presses from the key buffer.
6.5. Set Debounce
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
31
Key Presses On
Key Presses Off
Press
Buffer
Time
1 byte, debounce increment (debounce time =
1 byte, value of key pressed (MSB determines additional keys to be read)
Dec
Hex
ASCII
Dec
Hex
ASCII
Dec
Hex
ASCII
Dec
Hex
ASCII
Dec
Hex
ASCII
254 38
254 69
FE 26
FE 45
■ &
■ E
254 85
254 65
FE 55
254 79
FE 41
■ U
FE 4F
■ A
■ O
Time
Time
Time
Time
* 6.554ms)