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speed, user have to control the flow, if not the problem of data overflow on serial port side will occur. So data
flow is required to calculated when sending data from network to serial port.
Example:
Network sends data in m bytes every n seconds. Method of checking if there is overflow: ( Supposed
network condition is good and network data transmission time is negligible)
①
If there is no overflow, m bytes data must be transmitted within n seconds, then the transmitting time
of M bytes data:
If n >2T, then data will not overflow, USC520/USC540 can work normally. Just need keep n>T under baud
rate 9600.
3.4.9. Synchronous baud rate (RFC2217)
For encryption during data transmission, devices change data bytes, baud rate, parity and so on.
USC520/USC540 supports revise serial parameter accordingly.
Synchronous baud rate is named RFC2217. USR Similar RFC2217 make adjustments on the basis of
RFC2217 protocol to improve accuracy of transmission.
Protocol length is 8 bytes. And values taken for example is in HEX:
Name
Packet
Header
Baud Rate
Bytes parameter
Parity
Bytes
3
3
1
1
Explanation
reduce
misjudgment
High is in front,
smallest is
600(00 02 58)
data bytes, baud
rate, parity
Remove 4 bits
of header and
ignore the high
bit
(115200,
N,8,1)
55 AA 55
01 C2 00
03
46
(9600,
N,8,1)
55 AA 55
00 25 80
03
28
Serial parameter bit:
Bit #
Explanation
Value
Description
1:0
Data bit selection
00
5 bits
