Atmel SpW-10X user manual Command Packet Fill Bytes, Date 11 th July

SpW-10X Ref.: UoD_SpW-10X_

SpaceWire Router

UserManual

Issue: 3.4

User Manual Date: 11th July 2008

Figure 7-12 and Figure 7-13 illustrate how source path addresses are returned in relation to the RMAP packet description.

Dest Logical	Protocol ID	Command	Dest Key
00	00	04	02
Source Logical	Trans ID(1)	Trans ID(0)	Address(4)

Figure 7-12 Source Path Address field decoding

	Local Source	04	02
	Path Address
Source Logical	Protocol ID	Command	Status

Figure 7-13 Source Path Addresses in Reply Packet

7.6.10 Command Packet Fill Bytes

The Configuration port accepts packets which are addressed to port 0. In the RMAP command the next byte after the destination address 0 is the destination logical address byte (which in the router is expected to be the default 254 value). The format is shown in Figure 7-14.

Path

Address

0

Dest

Logical Protocol ID

Address 1

254

RMAP Header

Figure 7-14 Normal Configuration Packet Header Structure

To allow source nodes which have a 16, 24 or 32 bit access port then the configuration port accepts up to three null bytes at the start of the packet. The null bytes must be zero otherwise they will be treated as the destination logical address and an invalid destination logical address shall be recorded if the byte is not 254. The header with fill bytes is shown in the Figure 7-15.

Path

Address

0

Fill Byte

0

Fill Byte

0

Fill Byte

0

Dest

Logical

Address

254

Protocol ID

1

RMAP Header

Figure 7-15 Fill Bytes Configuration Header Structure

Note that the command packet fill bytes feature is specific to the SpW-10X router and is not part of the RMAP standard.

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