AT7913E
It provides hardware support for receiving two types of SpaceWire Transfer Protocols,
and can relay packets of other protocols to software. The SpaceWire Virtual Channel
Transfer Protocol (VCTP) implements multiple virtual channels (only one implemented
in SpaceWire-RTC) on a single SpaceWire link. The Remote Memory Access Protocol
(RMAP) implements remote memory access to resources in the node via
the SpaceWire link.
Data received over the link by the SpaceWire CODEC are temporarily stored in an
RxFIFO. Data are then stored to memory by the SpaceWire Module via direct memory-
access. Multiple Virtual Receive Channels (RxVC) can be used, each with its private
memory area to which data are written. In SpaceWire-RTC one channel (RxVC(1)) is
used for storing VCTP packets, and one channel (RxVC(0)) is used for storing RMAP
responses, RMAP commands not supported by hardware and packets of other types of
Transfer Protocols.
All RxVC share the same link. The SpaceWire Module implements hardware support for
the RMAP. RMAP is used for remotely accessing resources on the local AMBA bus. The
RMAP implementation can receive commands and generate responses, utilizing the
aforementioned RxFIFO and the TxFIFO.
Data to be sent are read by the SpaceWire Module from memory via direct memory
access. Data are then temporarily stored in a TxFIFO when forwarded to the SpaceWire
CODEC for transmission over the link. Multiple Virtual Transmit Channels (TxVC) can
be used, each with its private send list stored in memory from which data are read. In
SpaceWire-RTC one channel (TxVC(0)) is used for automatic RMAP responses, and
another channel (TxVC(1)) is used for transmissions set up by the user. All TxVC share
the same link. RMAP responses have priority over transmissions set up by the user. The
arbitration is performed for each packet sent.
4.11 JTAG Interface
The JTAG interface (compliant with IEEE-Std-1149.1) is used for the purpose of bound-
ary scan testing during manufacture and test of printed circuit boards hosting the ASIC.
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7833F–AERO–01/10
ATMEL [ ATMEL ]
