MVME340 Vme总线控制器模块

Description

MVME340 Vme总线控制器模块

MVME340 Vme总线控制器模块

Settings:
*1 trillion DRAM
* MOTOROLA MC68020RC20E,20 MHZ processor
*(2) 9-pin front panel serial port

Part Number(s): 01-W3440B13D, 01-W3440B13E, 01-W3440B07C

Estimated Shipping Size
Dimensions: 263 × 58 × 28mm
Weight:.4.3 kg
Country of Origin: United States of America

Three cross compilers hosted on a VAX/VMS for the Motorola 68020 processor hav e been evaluated . The target machine, a VME system with a MVME133 processor car d and a MVME340 digital i0-card, has been set up in an environment with a function generator and an oscilloscope in order to measure the real time response . The compilers supply the run time kernel . It is possible to use Ada for real time applications , with the use of optimization of accept statements task switch times can come down t o the order of 15 – 20 gs .

Ada has evolved drastically the last years . Soon after the language became an ANS I standard, only a few compilers were available and they could only be used to compil e a limited set of programs . We started out with nested generic packages and tas k types, only to find that some validated compilers were valid only for the test suite . The situation using these limited compilers was to spend a lot of time finding out wher e and why the compiler failed, either at compile or at run time .

The next step in the evolution came with what can be called production compilers for numeric and data handling programs . These compilers could replace most of th e existing Pascal and FORTRAN compilers . Tasking could be used for moderate tim e critical applications . Still the target machines were the same as the host, such as th e VAX . Several users and companies could now start to learn the language and start t o develop tools .

At that time Ada could replace most other languages for many applications . Th e language was primarily designed for real time applications and especially fo r embedded systems . The latest development in Ada compilers are cross compilers fo r quite powerful microcomputers like the Motorola 680X0-family, Intel 80X86 and National 32X32 . Hopefully there will be compilers for smaller micros in the future . In a project, aiming at distributing Ada software to a loosely coupled multi compute r system, three independent VME systems, with cpu, memory and Ethernet port, will b e used/1/ . The whole system will be programmed in Ada and it is therefore essential to choose a cpu-board and a compiler that supports low level programming and allow s an efficient mapping of hardware interrupts .

The three cross compilers that have been tested are the Alsycomp_011 from Alsysl2l , the System Designers Ada-Plus version 3A .00 /3/ and TeleGen2 /4/ fro m Telesoft/TeIeLOGIC . Cross compilers from VAX/VMS to Motorola 68000 not teste d here are available from Verdix and Tartan . Software tools and development support
The environment support is good enough for program development . There are , however, problems when the hardware and software do not match . If spuriou s interrupts occur, the system may hang, making it impossible to restart the program o r even get to the kernel . The kernel was downloaded into the target prior to the loadin g of the compiled and linked code . There is, of course, the possibility to use EPROM s for the kernel . During this evaluation, it was most convenient to download the kernel .

The environment is essential when developing programs on one computer to be run o n a separate target . However, the tests described in this article did not require an y debugging .