Matrix Orbital LK404-25 - Manual (Page 24)

20
5.2 Dallas One-Wire
Transaction Dec
Hex
ASCII 254 200 1
FE C8 01
■ ╚
STX
Flags Send Bits Receive Bits Data
Flags Send Bits Receive Bits Data
Flags Send Bits Receive Bits Data v5.0
Performs a single Dallas 1-Wire transaction. Consult your device documentation for information regarding device
specific protocols. If an error is encountered, a corresponding value will be returned by the device.
Flags Byte Flags for transaction, see below.
Send Bits Byte Number of bytes to be sent to the device.
Receive Bits Byte Number of bytes expected to be received from the device.
Data Byte(s) Data to be transmitted LSB to MSB.
Table 14: Dallas One-Wire Flags
Bit Flag Description
7
6 Unused
5
4 0 (Future Compatibility)
3 Add CRC8 to transaction
2 0 (Future Compatibility)
1 Read CRC8 from transaction
0 Reset Bus prior to transaction
Table 15: Dallas One-Wire Errors
Code Error Description
0 Success
1 Unknown Command
2 No Devices Found
3 Fatal Search Error
6.6 Keypad
6.1 Auto Transmit
Key Presses On Dec
Hex
ASCII 254 65
FE 41
■ A
v5.0
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
v5.0
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
Press Dec
Hex
ASCII 254 38
FE 26
■ &
v5.0
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 Byte Value of key pressed (MSb determines additional keys to be read).