Re: Andy Nonsense Malfunction now explained...
Mister Bryant, please! Still triggered by a mention of Sparc like a Pavlovian Doge after all these years. Don't you have some IBM overpriced software to laud?
Anyway, according to this little overview, the EDM is composed of two parts:
1) RTPU: "Remote Terminal & Power Unit installed on the underside of the Surface Platform and in charge of the Entry, Descent and Landing Sequence, not designed to survive the impact at landing as its job end at the shutdown of the landing engines." Interestingly, it seems to have no CPU, just FPGA logic .... ?
2) CTPU: "Central Terminal & Power Unit that is tasked with commanding all lander subsystems during surface operations, also directing power from the batteries to all powered components. It handles all onboard sequences, accepts science and housekeeping data, stores data and conditions data uplinks via UHF. The CTPU is built around a LEON Central Processor that represents the heart of a Processor Module which also hosts RAM and PROM memory, the onboard timer, a watchdog timer system, power converters and data input/output interfaces."
It seems that a LEON is "a 32-bit CPU microprocessor core, based on the SPARC-V8 RISC architecture and instruction set. It was originally designed by the European Space Research and Technology Centre (ESTEC), part of the European Space Agency (ESA), and after that by Gaisler Research. It is described in synthesizable VHDL ... The LEON project was started by the European Space Agency (ESA) in late 1997 to study and develop a high-performance processor to be used in European space projects. The objectives for the project were to provide an open, portable and non-proprietary processor design, capable to meet future requirements for performance, software compatibility and low system cost. Another objective was to be able to manufacture in a Single event upset (SEU) sensitive semiconductor process. To maintain correct operation in the presence of SEUs, extensive error detection and error handling functions were needed. The goals have been to detect and tolerate one error in any register without software intervention, and to suppress effects from Single Event Transient (SET) errors in combinational logic.
The Real-time operating systems that support the LEON core are currently RTLinux, PikeOS, eCos, RTEMS, Nucleus, ThreadX, OpenComRTOS, VxWorks (as per a port by Gaisler Research), LynxOS (also per a port by Gaisler Research), POK[ (a free ARINC653 implementation released under the BSD licence) and ORK+ an open-source real-time kernel for high-integrity real-time applications with the Ravenscar Profile.