Справочник Пользователя для Cable Electronics SW404HD

 
Address Byte (Command Type A and B) 

7  6 5 4 3 2  1  0 

BT X 

CRC 

M4 

M3 

M3 M1 M0 

Broadcast  Reserved 

CRC 

Machine ID (5-bit address) 

 
BT: Broadcast        0: Instruction for one machine with matching Machine ID 

1: Instruction for all machines 

 

If BT = 1, machine will not return a response packet.  
If BT = 0, machine must respond 
 
CRC: CRC-8 

0:  Host (computer) does not append a CRC byte at end of command 
packet 
1:  Host appends a CRC byte to end of command packet 

 
Instruction Code Byte (Command Type A and B) 

7  6 5  4 3 

2 

1 

0 

VAR X  I5  I4  I3 I2 

I1 

I0 

Variable 

Length 

Reserved  Instruction Code (6-bit command) 

 
VAR: Variable Length    0: The command packet is 4 bytes with Output and Input bytes 

1: The command packet is variable length and contains a 
length byte indicating the number of Output and Input bytes 

 
Length Byte (Command Type B only) 

L7 L6 L5 L4 L3 L2 L1 L0 

Number of Output and Input Bytes to follow not including CRC 

 
Output Byte (Command Type A and B) 

O7 O6 O5 O4 O3 O2 O1 O0 

Refer to Command Table 

 
Input Byte (Command Type A and B) 

I7 I6 I5 I4 I3 I2 I1 I0 

Refer to Command Table 

 
CRC (Command Type A and B) 

C7 C6 C5 C4 C3 C2 C1 C0 

CRC-8 calculated from all bytes in packet.  

Appended if CRC bit set in Instruction code