On 02/17/2015 11:16 AM, Viesturs Lācis wrote: > 2015-02-17 18:59 GMT+02:00 Jon Elson <[email protected]>: >> I use it here also to run a laser photoplotter, it unpacks >> run-length encoded >> raster files in real time between clocking out the pixels. > Could you, please, share more details about the software that controls > that machine? > > A short description is here : http://pico-systems.com/photoplot.html This was originally built using an ISA-slot DMA card in a Windows 95 computer. Win95 didn't allow enough memory for the aperture bitmaps, so I chopped the program in half. The raster generation ran on a Windows NT, and later Win2K system, then I sent the bitmap across the network to the plotter computer. I got all this working in 1996 or so, and left it untouched except when a bug was found in the Gerber to raster program about 2000. I wrote all the software in Borland's Turbo Pascal.
Well, I eventually feared the computer would die and leave me with no photoplotter. So, I used the PRU feature of the Beagle Bone Black to emulate the DMA card in the old PC. It needs to "prime the pipeline" with one write pulse when ready to plot a raster line, and then every 5 us the plotter will send an acknowledge pulse and the PRU needs to send the next raster bit. I used the run length encoding scheme because the PRU's local memories are quite small. I was able to hack up my old Turbo Pascal raster generation program to compile under the Free Pascal Compiler, which was written to handle Borland and DEC extensions to the original Pascal language. Mostly, I just used units. I cut away a bunch of vestiges from the original program which still thought it was controlling the plotter directly. It still creates double buffers, that was too deeply embedded in the program. Then, I can view the bitmap by converting to BMP format, or run it through another converter to turn it into the run length encoded file for the Beagle. This program does not handle RS-274X files, but I generally edit all the apertures anyway when making solder stencils to get the right amount of solder everywhere. It probably wouldn't be too hard to implement the RS-274X apertures, but would be a lot of work to implement all the special features that RS-274X can do with negative and positive flood polygons. If you want to experiment with it, I could probably let you have a copy. (I might need a non-disclosure agreement, though.) Jon ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=190641631&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
