Service manual

User Manual SD125E
Page 13
English
Serial Command
Serial RX/TX Data Format
(1) Asynchronous Serial Data Transfer
(2) Baud Rate : 4,800 bit/sec
(3) Data Bit : 8bit , Non Parity
(4) Stop Bit : 1bit
(5) MSB first transmission
Each serial command consists of 3 bytes.
1
st
byte is command and 2 is data required by command and 3
nd rd
is check sum to decide validity
of total contents.
Byte0
ST 1
st
Byte (Command) SP
Byte1
ST 2
Byte (Data) SP
nd
Byte2
rd
ST 3
Byte (Check Sum) SP
Receive Command & data
Mode Transmit
Comman
d
(BYTE0)
Transmit data
( BYTE1 )
Check sum( BYTE2 )
: Transmit Command
+ data
0xaa ACK Process
Complete
0x55 NACK
Commands
Note)
This command is return signal for receiving command.
If Byte2 and sum of Byte0 and Byte1 among received data are same, Radio would send
ACK data and execute command. If not, Radio sends Nack data.
User would go into next step if receives ACK data. If user receives Nack data, user
should send command again.
st
Channel to 2
nd
Channel,
example) If user changes from 1
User should send Channel Change Command (0x64,0x02,) ( 0x64 + 0x2 ) ) to Radio.
If Byte2 and sum of Byte0 and Byte1 among received data are same, Radio sends ACK
data to user and changes to 2
nd
channel. If not, Radio would send Nack data.