WATTIOCORP S.L. SERIE1 用户手册
Serial User Manual
Página 10
Figure 7: RTS/CTS Flow Control Connections
3.1.4.
Signal Operation
UART transport sends and receives data asynchronously. Data can be sent and received
simultaneously and the transfer of a frame can be initiated at any time by either the
application processor or the SERIE.
3.2.
General Frame Format
The general frame format is shown in the following figure. The left-most field is transmitted
first over the wire. For multi-byte fields, the lowest order byte is transmitted first.
Bytes:
1
2
0-250
Length Command
data
Figure 8: General Frame Format
Length: The length of the data field of the frame. The length can range from 0-250.
Command: The command of the frame.
Data: The frame data. This depends on the command field.
3.2.1.
Command Field
The command field is constructed of two bytes. The bytes are formatted as shown in the
following figure. The Cmd0 byte is transmitted first.
Cmd0
Cmd1
Bits:
7-5
4-0
7-0
Type
Subsystem
ID
Figure 9: Command field
Type: The command type has one of the following values:
•
0: POLL. A POLL command is used to retrieve queued data. This command is only
applicable to SPI transport. For a POLL command the subsystem and ID are set to zero
and data length is zero.
•
1: SREQ: A synchronous request that requires an immediate response. For example, a
function call with a return value would use an SREQ command.
SERIE
TX
CT
RX
RT
Host processor
RXD
TXD
CTS
RTS