OPERATION GUIDE
OG_STD-601B_v40e
Circuit Design, Inc.
23
13. RF data format
Data frame structure
A general data frame consists of Preamble, ID code, User data and Data-check and is
transmitted/received as a packet data. The data format below shows the one used for the STD-601
evaluation board.
Preamble
ID code
User data
Data-check
Dummy data
11001100....
CH
01
02
03
04
CC
CC
Repeated 0xCC
> 10 ms
1 byte
ID
4bytes
18 bytes
CRC
2bytes
2 bytes
Example data format
Preamble
A preamble is a dummy data to match the timing between transmission and reception. At the start of data
transmission, the transmitter transmits data including alternate low and high signals for a certain period of
time. A recommended preamble pattern is
11001100....of more than 10 ms (more than 20 ms is better).
ID code
An ID code is a unique code to identify own system from other systems. The receiver determines if the
received data is sent to itself. To avoid erroneous reception, it is recommended to use an ID code with
appropriate length.
User data
A user data is data the user intends to send/receive. To prevent data from being garbled, it is
recommended to use data that has periodical transitions between 1 and 0.
Data-check
A data-check (such as CRC) is used to check if the transferred data has errors or not. The receiver
determines if the received data is valid or not.
Dummy data
Following the data-check, a dummy data can be added as needed.
* The wireless communication of the STD-601 is asynchronous. UART is widely used since it has
advantages of easy data synchronization and periodic data transition with start/stop bits.
