{"id":1149,"date":"2020-11-18T21:21:26","date_gmt":"2020-11-18T21:21:26","guid":{"rendered":"https:\/\/pdp2011.sytse.net\/wordpress\/?p=1149"},"modified":"2020-11-18T21:21:26","modified_gmt":"2020-11-18T21:21:26","slug":"playing-around-with-minc","status":"publish","type":"post","link":"https:\/\/pdp2011.sytse.net\/wordpress\/playing-around-with-minc\/","title":{"rendered":"Playing around with MINC"},"content":{"rendered":"\n

In the first volume of the MINC book set ‘Introduction to MINC’ several demonstration programs are mentioned. These demonstration programs (and a few more) are on the demo diskette image that you can find on Bitsavers. And if you follow the process I described in the previous post, the demo programs will end up on the RK image.<\/p>\n\n\n\n

So, playtime. I selected the DADEM to give a try – a demonstration of the DA module.<\/p>\n\n\n\n

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For the D\/A part, I had already added a driver for the PMODDA2 – I had one of those lying around. Not ideal maybe, since it only has two channels, and it’s limited to 0V-3.3V – the original MNCAA could be set to 5 different voltage ranges with knobs on the front panel, up to -10.24V to +10.235V!<\/p>\n\n\n\n

Anyway, of course in my first experiments I hooked up my trusty digital voltmeter and everything worked great – but digital voltmeters do lack the proper mad scientist feeling that real meters with swinging needles give. So I just had to go into my storage room and dig out the box with old toys to find something more fitting.<\/p>\n\n\n\n

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And there it is. I’m not quite sure how old it is, but definitely older than I am – my dad took it home with him for his kids to play with, in the early 70s. It came from a laboratory instrument that his employer had discarded – probably a heavy power supply with lots of valves in it. For years the meter figured next to the transformer in various Fischer-Technik setups, later on I used it for my dangerous electrolysis prototypes… and it’s brother, taken from another instrument became the show piece on the front panel of my home made audio amplifier that I used in various offices until late in 1999. The amplifier is no more, but I still have the meter.<\/p>\n\n\n\n

Anyway, the demo. It makes the voltmeter swing around for a settable number of seconds, and it’s remarkably unimpressive – given that the range of 0V-3.3V is not really doing a lot on a 0-20V scale. I’ll have to look into level converters next. It’s not that bad with MNCAA really, but the ‘wrong’ input range conversion with MNCDA is a bit jarring – that needs fixed.<\/p>\n\n\n\n

For convenience, here’s the listing of the test program. If you are going to give it a go, take line 22 out – it will likely mess up the terminal emulator. Yes, it would be great if the terminal emulator in PDP2011 would be vt105 compatible… hmm, I’ll think about it.<\/p>\n\n\n\n

10 REM -----DADEM\n20 REM ----------Program to put analog out to digital volt ohmmeter\n22 DISPLAY_CLEAR\n30 PRINT 'DIGITAL-TO-ANALOG DEMONSTRATION PROGRAM' \\ PRINT\n40 PRINT 'The digital-to-analog demonstration program  generates a voltage'\n50 PRINT 'at the D\/A output causing the volt-ohmmeter to oscillate starting'\n60 PRINT 'with a small amplitude and slowly increasing until a maximum'\n70 PRINT 'amplitude is reached.'\n80 PRINT\n90 PRINT 'Connect the volt-ohmmeter to one of the four channels of the D\/A'\n100 PRINT 'converter.  Set the volt-ohmmeter to DC volts and select a range'\n110 PRINT 'that will give  full-scale deflection for a 5 volt input.'\n120 PRINT\n130 REM Request user input\n140 REM\n150 PRINT 'How many seconds do you wish to run (1 to 30)'; \\ INPUT T\n151 PRINT 'How many D\/A converters do you have in your configuration';\n152 INPUT N\n153 IF N>=1 THEN IF N<=4 THEN  GO TO 157\n156 PRINT 'please specify an integer between 1 and 4' \\ GO TO 151\n157 IF N>1 GO TO 600\n160 PRINT USING 'What channel did you connect the volt-ohmmeter to (0 to ##)',4*N-1; \\ INPUT C\n170 L=127 \\ M=.5 \\ A=16 \\ D=1 \\ V=0\n180 REM Schedule an interrupt T seconds from now\n200 S=0\n210 SCHEDULE('Interval',T,420)\n270 REM Repeat the following code until interval complete\n290 IF S=1 THEN 500\n300 AOUT(,V,,,C)\n310 GOSUB 330\n320 GO TO 290\n330 V=V+A*D\n334 IF D*V<ABS(L) THEN 400\n336 D=-D\n340 L=-L\n350 IF L<0 THEN 400\n360 IF L<200 THEN 380\n370 IF L<2000 THEN 390\n380 M=1\/M\n390 L=L*M\n400 RETURN\n410 GO TO 150\n420 REM Set the done flag.\n430 S=1\n440 RETURN\n500 PRINT  \\ PRINT 'AGAIN (Y or N)'; \\ INPUT A$\n510 IF A$='Y' THEN 120 \\ IF A$='y' THEN 120\n520 IF A$='N' THEN 800 \\ IF A$='n' THEN 800\n530 PRINT 'Please answer Y or N' \\ GO TO 500\n600 PRINT 'If you have followed the suggested configuration rules then your modules'\n601 PRINT 'are addressed as follows:' \\ PRINT\n602 PRINT 'The rightmost d\/a converter in the chassis has lines    0-3'\n610 PRINT 'The next d\/a converter to the left has lines:           4-7'\n620 IF N=2 THEN 700\n630 PRINT 'The next d\/a converter to the left has lines:           8-11'\n640 IF N=3 THEN 700\n650 PRINT 'The next d\/a converter to the left has lines:           12-15'\n700 GO TO 160\n800 END\n<\/pre>\n\n\n\n
Another thing with this test program – and the other one that I played around with, the DODEM for digital output – is that they use statements like SCHEDULE and PAUSE. Those require that the SJ monitor is sysgenned with timer support – if you didn’t, then those statements won’t work. And another thing: the sysgen needs to match the actual rate of the KW11 line clock in your system. Yes, I managed to get that wrong too \ud83d\ude09<\/p>\n","protected":false},"excerpt":{"rendered":"
In the first volume of the MINC book set ‘Introduction to MINC’ several demonstration programs are mentioned. These demonstration programs (and a few more) are on the demo diskette image that you can find on Bitsavers. And if you follow the process I described in the previous post, the demo programs will end up on […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[8],"class_list":["post-1149","post","type-post","status-publish","format-standard","hentry","category-minc","tag-minc","missing-thumbnail"],"_links":{"self":[{"href":"https:\/\/pdp2011.sytse.net\/wordpress\/wp-json\/wp\/v2\/posts\/1149","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdp2011.sytse.net\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pdp2011.sytse.net\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pdp2011.sytse.net\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pdp2011.sytse.net\/wordpress\/wp-json\/wp\/v2\/comments?post=1149"}],"version-history":[{"count":0,"href":"https:\/\/pdp2011.sytse.net\/wordpress\/wp-json\/wp\/v2\/posts\/1149\/revisions"}],"wp:attachment":[{"href":"https:\/\/pdp2011.sytse.net\/wordpress\/wp-json\/wp\/v2\/media?parent=1149"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pdp2011.sytse.net\/wordpress\/wp-json\/wp\/v2\/categories?post=1149"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pdp2011.sytse.net\/wordpress\/wp-json\/wp\/v2\/tags?post=1149"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}