Atmel SpaceWire Router SpW-10X User Manual

Ref.:   UoD_SpW-10X_ 

 

Issue:  3.4 

  

 

Date:  11

 

 

76

 

incrementing read 

4.  The data length is 

not 4 in a verified 

write command. 

5.  The data length is 

not 8 in a read 

modify write 

command. 

Invalid Register 
Address 

The address field is 
addressing an unknown 
register for a read command 
or a read only register in a 
write command. 

Yes 

RMAP Command not 
implemented or not 
authorised  

 

10 

Read Modify 
Write Data 
Length Error 

The read modify write data 
length is not 8 

Yes 

RMW Data Length Error 

11 

Invalid 
Destination 
Logical Address 

The destination logical 
address is invalid. The 
destination logical address is 
expected to be the default 
254 value 

Yes Invalid 

Destination 

Logical Address 

12 

 

7.6.7  Command Packet Cyclic Redundancy Check 

The header and data part of an RMAP packet are protected from errors by the use of an 8 bit CRC 
code. The header and data CRC is formed using the CRC-8 code used in ATM (Asynchronous 

Transfer Mechanism). CRC-8 has the polynomial: 

1

1

2

8

+

+

+

 with a starting value of 00h. 

Command packets received by the SpaceWire router which have an invalid header CRC are 
discarded and the Invalid Header CRC bit is set in the configuration port register. 

7.6.8  Local Source Path Address 

The configuration reply packet shall be routed out of the router port the packet arrived on. For 
example, if SpaceWire port 1 passed a configuration command to the configuration port then the reply 
packet is returned to port 1.