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In the scope of the "TopNet SpaceWire Controller / Remote User Interface" activity, ESA[1] funded some activities aimed at designing, manufacturing and validating a SpaceWire Remote Terminal Controller (SpW RTC), an embedded system for space applications, implemented as an ASIC with the primary objective is to provide the European space community with a ready to use, radiation-tolerant component.
 The SpW RTC device is going to be manufactured by Atmel using the radiation tolerant 0.18µm ATC18RHA technology. This single chip includes an embedded LEON2-FT SPARC V8 processor with a floating point unit, two SpaceWire interfaces, a controller area network (CAN) bus controller, ADC/DAC interfaces for analogue acquisition/conversion, and standard interfaces and resources (UARTs, timers, general purpose input and output).
The SpW RTC can be used both in non-intelligent nodes and in nodes with local intelligence, providing the remote terminals with increased autonomy and hence relieves the central processing chain of repetitive standard acquisition and management duties.
In the frame ESA LET-SME initiative, Aurelia Microelettronica is developing a SpW RTC suite, useful to test each application integrating a SpW RTC device, making easier the integration and test phases and reducing the time-to-market.
The SpW RTC development suite consists of two interconnected HW modules capable to stimulate all the device interfaces.
The "PCI-SpW/CAN" module (A1493) is a flexible FPGA based device that can be configured to work inside a PC as a PCI peripheral board, or be enclosed in an external USB case with up to 2 CAN, 2 MILSTD 1553B and 8 SpaceWire ports. The minimal PCI configuration with 2 CAN +2 SpW ports is sufficient to allow a standard Linux PC to communicate via SpaceWire and/or CAN with the RTC device.
The "RTC Test Bed" board (A1494) houses the RTC device under configuration-test providing it with the memory resources and the FIFO/ADC samples needed to exercise all its interfaces. In addition, a hot plug option is foreseen to plug in a custom mezzanine board for specific applications.
The Suite SW library offers an efficient low-level application programmer interface to operate the CAN network management and the remote RTC control using the RMAP protocol on SpaceWire.
The two boards can work independently each from other: the "RTC Test Bed" can be connected to third part network interfaces and also the "PCI-SpW/CAN" board can be used for different CAN or SpW devices. In addition several innovative concepts are embedded in the “PCI-SpW/CAN” board:
- Compactness. Two CAN Controllers and two SpaceWire ports are hosted on the same single board.
- Flexibility. CAN and SpW modules are RTL Core instances embodied in large FPGA. They can be easily modified and/or enhanced to follow any new protocol updates. This is a strong advantage considering that the SpW RMAP is actually in the draft form.
- Maintainability. A custom FPGA programming scheme (Aurelia A-AltPrg[2]) is implemented on the board to allow the users to update the FPGA image without need of any vendor specific SW/HW tool or licence. The users can load the new programming image directly through the PCI bus.
- Expandability. The utilisation of a large and fast FPGA (Altera Stratix II) is planned to leave the possibility to expand its embodied functionalities in a future development. For example it could be the case of an HW support for the CAN-Open Layer.
- Simplicity. The programmer is provided with a single API for all the communication links. All the internal buffers and control registers are easily accessible because they are mapped in an uniform memory segment in the PCI space.
The main building blocks composing the SpW RTC Development Suite are two interconnected HW modules and a dedicated SW library. The required host environment is a common desktop PC with Linux operating system.
The Development Suite SW library includes the driver and communication layer needed to utilize the PCI SPW/CAN board hosted the Test PC in order to exchange data with the RTC ASIC through the SpW and CAN links. The RMAP on SpW protocol capabilities of the Suite can be exploited to access the SPW-RTC memory space.
[1] European Space Agency
[2] A-AltPRG is the Aurelia integrated solution for Altera FPGA programmability on-board, without need of proprietary software and external cables.
Support for SpW RTC suite: please click
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