User's Manual

Viewsonic Tweety RF Remote Rev 2.9A November 05, 2001
Universal Electronics Inc. Confidential Page 34 of 63
3.4.6.1 Firmware Unit:
This so-called “unit” is
actually a firmware portion
that processes to keep 5 bytes of the 11-byte
data packet after striping off all the Sync bytes and Preamble bytes. It then output these 5 bytes
through the RS-232 protocol format.
Byte4 Byte3 Byte2 Byte1 Byte0
Device Number DevAddr/Status X-coordinate
Y-coordinate /
Scan Code
CheckSum
(8 bits) (8 bits) (8 bits) (8 bits) (8 bits)
Byte0
CheckSum
The result of the addition (without carry) of Byte1 through Byte4
(Device Number + Device Address / Status + X-coordinate + Y-coordinate /
Scan Code)
Byte1
Y-coordinate / Scan Code
Y-data for Remote Control Pointing Device, or
Make/Break Scan Code of the pressed/released key on the Remote Control
Keypad. See Table2 for details.
Byte2
X-coordinate
X-data for Remote Control Pointing Device.
Always 0 for Remote Control Keypad
Byte3
Device Address / Status
Please refer to details on next page
Byte4
Device Number
Device Number is chosen from 0 to 99 by system Host interface. The Host
will validate the received data packet by checking the Device Number if it is
registered for that device.