Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!samsung!uunet!mcsun!hp4nl!rulway.LeidenUniv.nl!rulcvx.LeidenUniv.nl!breemen From: breemen@rulcvx.LeidenUniv.nl (E. van Breemen) Newsgroups: comp.sys.amiga.hardware Subject: Re: 14 Mhz Hack Message-ID: <1991May16.093917.28260@rulway.LeidenUniv.nl> Date: 16 May 91 09:39:17 GMT References: <1991May13.081500.7980@rulway.LeidenUniv.nl> Sender: root@rulway.LeidenUniv.nl (System PRIVILEGED Account) Organization: Leiden University, the Netherlands. Lines: 69 Nntp-Posting-Host: rulcvx.leidenuniv.nl In article billc@cryo.UUCP (William J. Coldwell) writes: >manufacturer's item] when doing [CPU or DMA action]. This in-turn causes >a rush to the [name] board layout package for the changes necessary to make >the [your product] work with the latest rev, reducing the meager profit >margin." ;-) This is true if you are pushing your board to the edge of performance. You can do that by ignoring the specs of Commodore. It is to be expected that there are then some incompatibilities. The patch needed for repairing this will be (most of the times) something more than reprogramming a PAL. Besides that PALS are expensive if you compare them to normal logic. For example if you need flipflops to be clocked on different clocks (like in my design) you need a PAL of say $15 for a $3 logic equivalent. Cheap PALS do have flipflops, but they have to be clocked with the same clock. These PALS are of great value for address decoding and auto configuration. >The 14MHz hack will only give you a limited experience on how to deal >It's reliability was about what is expected on the board of that size >in a noisy A1000 running at that speed ;-). No, first of all you HAVE to use a datalatch for the interface to the Amiga (for an asyn. board). Certainly not some tricky delay, which depend on the kind of logic you use. Second, the FPU will also respond to MMU instructions because the interface of the CPU and the FPU is not correct. And given a noisy behaviour at 16 Mhz, you get an unreliable board. The most important lesson of the 14 Mhz hack was that you can't avoid the rules without paying a price. >>Commercially spoken yes, but for people who don't have enought money, >>say $500, it can be interesting. > ><$500 will still get a nice speedup. You can get a 25MHz Mega Midget >Racer (030) for about that price. I suppose this a board without 32bit ram. If so, you have to buy addional ram for $xxx. Otherwise, the speed increase can be little (30-40%?) because the 68020 and the 68030 will get their performance from a 32bit memory. The prices in Holland are much higher. A 68030 board without ram, will cost you at least Hfl. 1900,- ($1000). In Germany DM 1600,- with 1MB 32bit ram ($1000). In Holland, it is very difficult to get hardware besides the A500, A590 and the A2000. The drives are expensive ($300 for 3.5"). The first A3000 I have seen will cost you here Hfl. 10500,- ($5300). (BTW the Commodore support in Holland can be improved. As I asked for detailed schemes of the A500 , I got a normal commercial folder.) My point is that such a board of say $50 can be very interesting in Holland. And it is still possible to add a FPU to this cheap board. Most people don't have $1000 to spend, to accelarate a machine of $500. Why do you think I am busy building an 68020 board? I can get the components for say $150. I have (I may hope so) a knowledge of electronics and the Amiga. It should therefore be possible to build what you want. If you don't have the money, you have to use your brains instead. >SMD to me, no longer denotes a "hack". ;-) Yeap, more (I hope) a reliable board. Erwin. PS. I have received the last days many requests for a copy of the schemes. I won't send anyone a copy because: 1) It is to much work. 2) I will present the schemes in due time on the net. So, please, don't ask for schemes. I will not send it to you. Have patience for 2 months. I hope everyone can understand this. And Commodore, don't take the criticism on Commodore Nederland personal, your support on this net is great!