The GRSPW2 core implements a SpaceWire link controller with RMAP support and AMBA host interface. The core complies to the SpaceWire standard (ECSS-E-ST-50-12C) with the protocol identification extension (ECSS-E-ST-50-51C) and RMAP protocol (ECSS-E-ST-50-52C). Receive and transmit data is autonomously transferred between the SpaceWire Codec and the AMBA AHB bus using DMA transfers. Through the use of receive and transmit descriptors, multiple SpaceWire packets can be received and transmitted without CPU involvement. The GRSPW2 control registers are accessed through an APB interface. For critical space applications, a fault-tolerant (FT) version of GRSPW2 is available with full SEU protection of all RAM blocks.
GRSPW2 is the successor to the GRSPW. It is based on the old core and contains all of its functionality and features while also adding new ones. The major differences are shown in the table below.
Feature | GRSPW | GRSPW2 |
RMAP | Draft C | Draft F |
Clock factor | 4 | 8 |
DMA channels | 1 | 4 |
Timers | System clock | SpaceWire clock |
Addressing | Single address | Multiple addresses and ranges |
The GRSPW2 increased speed comes with an area penalty compared to the GRSPW. The table below shows the approximate Cell/LUT count and frequency for eight different GRSPW2 configurations on Actel RTAX, Xilinx Spartan3, Xilinx Virtex2 and ASIC technologies.
(Cells / RAM blocks / AHB MHz / SPW Rx Mbps)
Core configuration | RTAX | RTProASIC3 | Virtex5 | ASIC | |
GRSPW2 | 4,200 / 3 / 60 / 250 | 5,800 / 5 / 45 / 180 | 1,800 / 3 / 130 / 400 | 15,000 gates | |
GRSPW2 + RMAP(1) | 5,800 / 4 / 60 / 250 | 8,500 / 6 / 45 / 180 | 2,700 / 4 / 130 / 400 | 20,000 gates | |
GRSPW2 + 2P(2) | 4,400 / 3 / 60 / 250 | 6,100 / 5 / 45 / 180 | 1,800 / 3 / 130 / 400 | 15,000 gates | |
GRSPW2+4DMA(3) | 5,400 / 3 / 60 / 250 | 7,400 / 5 / 45 / 180 | 2,200 / 3 / 130 / 400 | 19,000 gates | |
GRSPW2+ RMAP + 2P + 4DMA | 7,400 / 4 / 60 / 250 | 10,200 / 6 / 45 / 180 | 3,300 / 4 / 130 / 400 | 26,000 gates | |
GRSPW2-FT(4) | 4,300 / 5 / 60 / 250 | 6,000 / 10 / 45 / 180 | 1,800 / 5 / 130 / 400 | 15,000 gates | |
GRSPW2-FT + RMAP | 5,900 / 6 / 60 / 250 | 8,500 / 12 / 45 / 180 | 2,800 / 6 / 130 / 400 | 21,000 gates | |
GRSPW2-FT + RMAP + 2P + 4DMA | 7,200 / 6 / 60 / 250 | 10,400 / 12 / 45 / 180 | 3,400 / 6 / 130 / 400 | 26,000 gates | |
(1) Includes the RMAP command handler (2) Dual SpaceWire ports. One is available in the standard configuration |
(3) 4 DMA channels. One is available in the standard configuration (4) Fault tolerant version |
Features
Benefits
Deliverables