Table of Contents
Advertisement
2.2
Operation Modes
According to the different protocol formats expected for the operation of the SMCS332SpW, two major operation modes are
implemented into the SMCS332SpW. The operation modes are chosen individually for each link channel by setting the
respective configuration registers via the HOCI or via the link.
•
Transparent Mode (default after reset): This mode allows complete transparent data transfer between two nodes
without performing any interpretation of the data bytes and without generating any acknowledges. It is completely
up to the host CPU to interpret the received data and to generate acknowledges if required.
The SMCS332SpW accepts EOP and EEP control tokens as packet delimiters and generates autonomously EOP or
no EOP (as configured) marker after each end of a transmission packet.
This mode also includes as a special sub mode:
•
Wormhole routing: This mode allows hardware routing of packets by the SMCS332SpW.
•
Simple Interprocessor Communication (SIC) Protocol Mode: This mode executes the simple interprocessor
communication protocol as described in chapter 13. The following capabilities of the protocol are implemented into
the SMCS332SpW:
•
interpretation of the first 4 data characters as the header bytes of the protocol
•
autonomous execution of the simple control commands as described in the protocol specification
•
autonomous acknowledgement of received packets if configured
In transmit direction no interpretation of the data is performed. This means that for transmit packets, the four header
bytes must be generated by the host CPU and must be available as the first data read from the communication
memory. EOP control characters are automatically inserted by the SMCS332SpW if one configured transfer from
the communication memory has finished.
2.3
SMCS332SpW Control by SpaceWire link
A feature of the SMCS332SpW is the possibility to control the SMCS332SpW not only via HOCI but via one of the three
links. This allows to use the SMCS332SpW in systems without a local controller (µController, FPGA etc.). Since the HOCI
is no longer used in this operation mode, it is instead available as a set of general purpose I/O (GPIO) lines. The detailed
description of this operation mode is given in section 5.4.
2.4
Wormhole Routing
The SMCS332SpW introduces a wormhole routing function similar to the routing implemented in the SpaceWire Router.
Each of the three links and the SMCS332SpW itself can be assigned an eight bit address. When routing is enabled in the
SMCS332SpW, the first byte of a packet will be interpreted as the address destination byte, analyzed and removed from the
packet (header deletion). If this address matches one of the two other link addresses or the SMCS332SpW address assigned
previously, the packet will be automatically forwarded to this link or the FIFO of the SMCS332SpW. If the header byte does
not match a link address, the packet will be written to the internal FIFO as well and an error interrupt (maskable) will be
raised.
SMCS332SpW
User Manual
– All Rights Reserved – Copyright per DIN 34 –
EADS Astrium GmbH, ASE2
Doc No: SMCS_ASTD_UM_100
Issue:
1.4
Updated: 9-Sep-2006
Page:
11 of 131
Advertisement
Table of Contents
