COBHAM GR712RC User Manual

GR712RC-UM, Jun 2017, Version 2.9 103 www.cobham.com/gaisler
GR712RC
16 SpaceWire Interface with RMAP support
16.1 Overview
The SpaceWire core provides an interface between the AHB bus and a SpaceWire network. It imple-
ments the SpaceWire standard [SPW] with the protocol identification extension [RMAPID]. The
Remote Memory Access Protocol (RMAP) command handler implements the ECSS standard
[RMAP].
The SpaceWire interface is configured through a set of registers accessed through an APB interface.
Data is transferred through DMA channels using an AHB master interface.
GR712RC includes six GRSPW2 cores. Only cores GRSPW2-0 and GRSPW2-1 include RMAP sup-
port. Each core includes a single DMA channel. Each core supports a single port.
Note that the subsequent sections are written in a generic manner as if there were several DMA chan-
nels, even though there is only one channel per core.
16.2 Operation
16.2.1 Overview
The GRSPW can be split into three main parts: the link interface, the AMBA interface and the RMAP
handler. A block diagram of the internal structure can be found in figure 59.
The link interface consists of the receiver, transmitter and the link interface FSM. They handle com-
munication on the SpaceWire network. The AMBA interface consists of the DMA engines, the AHB
master interface and the APB interface. The link interface provides FIFO interfaces to the DMA
engines. These FIFOs are used to transfer N-Chars between the AMBA and SpaceWire domains
during reception and transmission.
The RMAP handler handles incoming packets which are determined to be RMAP commands instead
of the receiver DMA engine. The RMAP command is decoded and if it is valid, the operation is per-
formed on the AHB bus. If a reply was requested it is automatically transmitted back to the source by
the RMAP transmitter.
Figure 59. Block diagram
TRANSMITTER
RXCLK
TXCLK
RXCLK
TRANSMITTER
FSM
LINKINTERFACE
SEND
RMAP
D(1:0)
S(1:0)
FSM
RECOVERY
RECEIVER0
RXCLK
RECOVERY
RXCLK
FSM
TRANSMITTER
DMA ENGINE
RECEIVER
DMA ENGINE
TRANSMITTER
RMAP
RECEIVER
N-CHAR
FIFO
RECEIVER
AHB FIFO
RECEIVER DATA
PARALLELIZATION
AHB
MASTER INTERFACE
REGISTERS
APB
INTERFACE
D0
S0
S1
RECEIVER1
D1

COBHAM GR712RC Specifications

General

Brand	COBHAM
Model	GR712RC
Category	Computer Hardware
Language	English