Date: Mon, 5 Apr 2010 18:18:33 -0400 From: Ethan Dicks <ethan.dicks at gmail.com> Subject: Re: Anyone have an image of a Japanese PET chrgen ROM 901447-12? On 4/5/10, M H Stein <dm561 at torfree.net> wrote: Why would the key be wrong? *MS: What I meant was that one of my keys might have been replaced; the picture of the chiclet keyboard has a Yen symbol, the normal graphic symbol and a Japanese character where the \ key usually is, whereas my keyboard just has the normal \ and graphic symbol. --- I have not. If you could send me a copy of it off-list, that would be appreciated. I don't seem to have it in the place I store such things (though I do remember the conversation). *MS: I'll send you the binaries, character charts and pics of the keyboard off-list. --- How would that work? Obviously, you'd use some new means of toggling upper bits on the CHRGEN ROM, but I don't get how the reverse video signal would be the trigger... the upper bit on a PET character cell inverts the data out of the bit shifter (unlike the C-64 where it's just another address bit). I can see how you could steal that upper bit and pipe it into A11 on a larger CHRGEN ROM, but how do you get 3 or 4 sets from one bit? *MS: As you know, PETS have two mutually exclusive sets, upper/lower case or upper case/graphics; when you install the Japanese characters you have to give up at least one of those half-sets and you can't for example have Japanese characters and upper/lower Roman characters on the same screen, not to mention graphics. I haven't looked at the older PETs to see if/how it might be feasible, but the newer ones with a CRT controller have provision for selecting an alternate character set with one of the unused address lines, so I thought it might be easily possible to use that somehow, perhaps even connecting it to the reverse video signal so that the RVS on/off key would select the alternate set on an individual character basis and allow mixing (e.g.) Japanese, upper, lower and graphics characters, all on the same screen instead of switching the mode of the whole screen with the text/graphic poke. mike