Atmel SpaceWire Router SpW-10X - Manual (Page 65)

Ref.: UoD_SpW-10X_
UserManual
Issue: 3.4
SpW-10X
SpaceWire Router
User Manual Date: 11 th
July 2008
Preliminary
65
Command
Byte
Read incrementing address reply command byte. The packet type bits in the
command byte indicate this packet is a reply packet.
1
Status The command status is returned in this field. The command status can be
command successful or an RMAP error code as defined in section 7.6.6.
1
Destination
logical
address
The destination logical address is set to the default value FEh as the
SpaceWire router does not have a logical address.
1
Transaction
Identifier
The transaction identifier identifies the command packet and reply packet with a
unique number. The transaction identifier in the reply packet is copied from the
command packet and returned in this field, so that the command and the
corresponding reply have the same transaction identifier value.
2
Data
Length
The data length field is the number of bytes read from the router as specified in
the data length field of the command packet.
3
Header
CRC
The header CRC used to detect errors in the header part of the command
packet. See section 7.6.7 for CRC generation.
1
Data The data read from the registers in the device. The data is returned in 32 bit
words starting from the address specified in read address in the command
packet.
>=4
Data CRC The data CRC used to detect errors in the data part of the reply packet. See
section 7.6.7 for CRC generation.
1
7.6.4 Read Modify Write Command
The read-modify-write command characteristics are defined in Table 7-8.
Table 7-11 Read-Modify-Write Command Characteristics
Action Supported/
Not Supported
Maximum number
of bytes Non-aligned access
accepted
8-bit read-modify-write NS - -
16-bit read-modify-write NS - -