Midland SD-250, User Manual, Page: 12 / 20

Rev. 0B
11
Byte0
Start bit 1
st
8-Bits (Command) Stop bit
Byte1
Start bit 2
nd
8-Bits (Data) Stop bit
Byte2
Start bit 3
rd
8-Bits (Check Sum) Stop bit
Available Command and Data format
Mode
Command
(1
st
8-Bits)
Data
( 2
nd
8-Bits)
Check sum ( 3
rd
8-Bits )
: C Data
1. Channel Change 0x64 0xXX :Current channel ( 0x64 + Channel )
2.
RTX Mode Selection
0x61 R(0x72) : Rx mode
T(0x74) : TX mode
( 0x61+ 0x72 )
( 0x61+ 0x74 )
3.
Modem test mode
0x75 0x78 : Enable test data
0x79 : Disable test data
( 0x75 + 0x78 )
( 0x75 + 0x79 )
GMSK
0x7a 0x00 : Disable
0x01 : Enable
( 0x7a + 0x00 )
( 0x7a + 0x01 )
0x7c 0x00 : Disable
0x01 : Enable Mark data
( 0x7c + 0x00 )
( 0x7c + 0x01 )
4.
Modem
alignment
mode
FFSK
&
AFSK
0x7e 0x00 : Disable
0x01 : Enable Space data
( 0x7e + 0x00 )
( 0x7e + 0x01 )
5. Radio Reset 0x86 0x01 ( 0x86 + 0x01 )
example) In order to change channel from 1 to 2,
0x64, 0x02, ( 0x64 + 0x2 ) should be applied to Radio in order.
Note) To clear memory buffer for serial command in Micro-controller, its 3 bytes
buffer should be filled up. On getting 3 consecutive bytes, MCU automatically
decides its correct action and then clear its memory immediately.