ACC-72EX User Manual
DPRAM Data Processing
56
Hilscher Documentation
ACC-72EX Setup Assistant
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usWaitingPackages
SRMB_usWaitingPackages
ulDest
SRMB_ulDest
ulSrc
SRMB_ulSrc
ulDestId
SRMB_ulDestId
ulSrcId
SRMB_ulSrcId
ulLen
SRMB_ulLen
ulId
SRMB_ulId
ulState
SRMB_ulState
ulCmd
SRMB_ulCmd
ulExt
SRMB_ulExt
ulRout
SRMB_ulRout
…
SRMB_ultData0 .. SRMB_ultData20
The size of a packet is always at least 40 bytes. Depending on the command, a packet may or may not
have a payload in the data field (tData). If present, the contents of the data field are specific to the
command or reply.
Destination Queue Handler
The ulDest field identifies a task queue in the context of the netX firmware. The task queue
represents the final receiver of the packet and is assigned to a protocol stack. The ulDest field has
to be filled out in any case; otherwise, the netX operating system cannot route the packet.
Source Queue Handler
The ulSrc field identifies the sender of the packet. In the context of the netX firmware (inter-task
communication), this field holds the identifier of the sending task. Usually, a UMAC program
uses this field for its own handle, but it can hold any handle of the sending process. The receiving
task does not evaluate this field and will pass it back unchanged to the originator of the packet.
Destination Identifier
The ulDestId field identifies the destination of an unsolicited packet from the netX firmware to
the UMAC. It can hold any handle that helps identify the receiver. Its use is mandatory for
unsolicited packets. The receiver of unsolicited packets has to register for this service (details are
yet to be determined).
Source Identifier
The ulSrcId field identifies the originator of a packet. This field is used by a UMAC program
which passes a packet from an external process to an internal netX task. The ulSrcId field holds
the handle of the external process. When the netX operating system returns the packet, the
UMAC program can identify the packet, and returns it to the originating process. The receiving
task on the netX does not evaluate this field, and passes it back unchanged. For inter-task
communication, this field is not used.
Length of Data Field
The ulLen field holds the size of the data field tData in bytes. It defines the total size of the
packet’s payload that follows the packet’s header. Note that the size of the header is not included
in ulLen. Depending on the command or reply, a data field may or may not be present in a packet.
If no data field is used, the length field is set to zero.