ROM0 is 28 pins. I went downstairs to open it up again and count... can't be 27c1001. that's 32 pins as you say Mike.
so, still a mystery. I thought maybe it could just be a 64k ROM - that clearly can fit in a 28pin socket. Steve On Fri, Feb 17, 2017 at 8:13 PM, Stephen Adolph <[email protected]> wrote: > oh that's very interesting. ok. I wonder what the pin assignment is. > > what does the 8300 need 96k of rom for 8300 mode for, vs only 32k rom for > 8201? > > a schematic would be golden. All I can say is there is no other ROM > on the board. > > Steve > > On Fri, Feb 17, 2017 at 6:51 PM, Kurt McCullum <[email protected]> wrote: >> I don't have an 8300 here but web8201.net has some detailed technical docs. >> Here is a page describing the PROM as 128k >> >> http://web8201.net/NEC8201emulation.asp >> >> Kurt >> >> -----Original Message----- >> From: M100 [mailto:[email protected]] On Behalf Of Stephen >> Adolph >> Sent: Friday, February 17, 2017 2:53 PM >> To: Model 100 Discussion <[email protected]> >> Subject: Re: [M100] Parts for an NEC PC-8300 >> >> from my perspective- >> >> * there is a single socket ROM0 for the main ROM >> * ROM1 is for option roms. >> * there is no other ROM in the unit. >> * it is a 32pin socket, and so it must be no larger than a 64kB rom. >> Not likely to be 32kB. >> * i'd bet that OUT163,2 sets A15 on the socket. >> * no idea what the pinout is but it could be deduced quickly. I think since >> the PC8201 uses normal pinouts, so too does the 8300. >> >> So my bet would be a 27C512 would do it. It is possible however that it is >> still just a 32kB rom. Perhaps OUT163,2 sets a signal on the PIO or >> otherwise that the processor can check, to decide what mode it should be in. >> >> Steve >> >> >> >> On Fri, Feb 17, 2017 at 4:19 PM, Frederick Whitaker <[email protected]> >> wrote: >>> Mike >>> >>> There are places for two ROMS. In the regular PC-8300 there is only >>> one ROM used for Basic. >>> 83100 - 438 >>> N83A Basic >>> 1986 >>> Microsoft >>> 8649 - Z69 >>> >>> In the other unit, which no longer has it's regular ROM, there are two ROMs >>> D276256D-20 >>> D276256G-25 >>> >>> I hope this helps. On the PC-8300 there is a wide access on the back >>> with three screws. Only two ROM sockets are visible and usable without >>> dismantling the case. >>> >>> I hope this helps. >>> >>> Fred Whitaker >>> >>> >>> On 2/17/2017 2:15 PM, Mike Stein wrote: >>>> >>>> Looks like it's up to you, Fred: >>>> >>>> Can you open up the 8300 and tell us exactly how many and what kind >>>> of ROMs or EPROMs are in there, i.e. any labels and/or part numbers? >>>> >>>> Since at least one is custom firmware it's probably in an EPROM (as >>>> opposed to a ROM) and will probably have a standard number like 27C512. >>>> >>>> From what I've read it looks like there should be three 28-pin >>>> sockets with a 27C512 in two of them and the third one empty or with >>>> an Option ROM in it. >>>> >>>> Let me know what you find. >>>> >>>> m >>>> >>>> ----- Original Message ----- >>>> From: "Fred Whitaker" <[email protected]> >>>> To: "Model 100 Discussion" <[email protected]> >>>> Sent: Sunday, February 12, 2017 3:32 PM >>>> Subject: Re: [M100] Parts for an NEC PC-8300 >>>> >>>> >>>>> Mike >>>>> >>>>> I don't have an image. I don't know if the ROM you are referring to >>>>> will do the job. The 8300 ROM is bigger than the 8201, but I believe >>>>> it uses the same chip as the 8201. >>>>> >>>>> I was under the impression that someone had uploaded a copy of the >>>>> 8300 ROM contents, but I don't remember where or when. >>>>> >>>>> I could send you one of my ROMs, from another machine, but I don't >>>>> know if that would help. >>>>> >>>>> Fred Whitaker >>>>> >>>>> On 2/11/2017 7:48 PM, Mike Stein wrote: >>>>>> >>>>>> Hi Frederick, >>>>>> >>>>>> If you can send me or point me to an image of that ROM I can >>>>>> probably burn an EPROM for you, assuming it's a JEDEC-standard 27xxx >>>>>> type. >>>>>> >>>>>> m >>>>>> >>>>>> ----- Original Message ----- >>>>>> From: "Frederick Whitaker" <[email protected]> >>>>>> To: "Model 100 Discussion" <[email protected]> >>>>>> Sent: Saturday, February 11, 2017 6:27 PM >>>>>> Subject: [M100] Parts for an NEC PC-8300 >>>>>> >>>>>> >>>>>>> I am interested in a replacement keyboard for my NEC PC-8300. I >>>>>>> also need a new Main ROM, When I received this machine it had a >>>>>>> specialized ROM in it. It will not boot. >>>>>>> >>>>>>> If I had those two items I could use this machine. I have asked in >>>>>>> the past if anyone could make a main ROM for this machine but >>>>>>> never received an answer. >>>>>>> >>>>>>> Fred Whitaker >>> >>> >>
