https://microcorelabs.wordpress.com/2023/04/28/ibm-pc-8088-replaced-with-a-motorola-68000/ Skip to content [ted_2878] MicroCore Labs Ted Fried's Project Blog Sidebar Menu Search for: [ ] [Search] Recent Posts * Convert an Apple II into an Apple 1 using MCL65+ * IBM PC 8088 replaced with a Motorola 68000 * MDA Video SOC FPGA Project * IBM 5151 Repair * Oscilloscope Art using X-Y Mode Recent Comments IBM PC 8088 replaced... on IBM PC 8088 replaced with a Mo... IBM PC 8088 changed... on IBM PC 8088 replaced with a Mo... IBM PC 8088 replaced... on IBM PC 8088 replaced with a Mo... HackerNews Summary (... on IBM PC 8088 replaced with a Mo... IBM PC 8088 replaced... on IBM PC 8088 replaced with a Mo... 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It can be used as a drop-in replacement for the Intel 8088 and can be cycle accurate as well as run in accelerated modes. [image-6] For this project I swapped the 8088 emulation code with my MCL68 code which emulates the Motorola 68000. The 8088 local bus emulation was kept so that all of the 68000's memory reads and writes could pass through to the IBM motherboard. Emulating the 68000 is fine, but not very useful without an operating system or some other application to run on it. I chose to use Gordon Brandley's 68K BASIC which was published in Dr. Dobbs Journal back in 1985. [image-7] I should note that just the 68000 emulation is running inside of the MCL86+. All of the IBM motherboard peripherals, video, and memory are used for this project. Video is drawn to the IBM MDA card's video memory over the ISA bus. BASIC is run out of 64 KB of the motherboard DRAM which is refreshed by the 8327 DMA controller by an interval set by the 8253. The keyboard receives the serial data and generates an interrupt through the 8259 and is cleared by accesses to the 8255. Basically all of the major components and glue logic of the IBM motherboard are used! I ran a few tests and it seems that there is not much of a performance difference between running an 8088 and a 68000 on the IBM motherboard which uses 8-bit chips exclusively. If IBM had chosen the 68000 they may actually have used the 68008 which is a 68000 with an 8-bit local bus interface. Perhaps this chip was not available at the time IBM's project, code-named 'Chess', was in development. It could also have been the case that Microsoft did not have an operating system or BASIC ported to the Motorola 68000 architecture. What this project shows is that the performance difference was not so profound that it would have made a difference in IBM's selection process. Here are some videos of the machine in action: I hope this project helped satisfy those who have wondered what the IBM Personal Computer would have been like if they had selected the Motorola 68000 instead of the Intel 8088! Advertisement Share this: * Twitter * Facebook * Like this: Like Loading... IBM PC 8088 replaced with a Motorola 68000 Post navigation - MDA Video SOC FPGA Project Convert an Apple II into an Apple 1 using MCL65+ - 10 thoughts on "IBM PC 8088 replaced with a Motorola 68000" 1. [croppe] Ted Fried Rewrites Historical past with a Motorola 68000-Powered IBM PC, Because of a Teensy 4.1 Mod - Slsolutech.Best IT Related Website says: [...] Fried's full write-up is accessible on his weblog. [...] LikeLike April 29, 2023 at 6:31 pm 2. [croppe] IBM PC 8088womotorora68000niBian Geng - Shi Jie noHua Ti woRi Ben Yu dezatsukuriSu Zao kuQue Ren ! says: [...] konoJi Shi haHackerNewsniJie Zai saretaXia Ji noJi Shi oyobisoreniDui suru HackerNewsShang nokomentowoYuan niZuo Cheng sareteimasu. IBM PC 8088 replaced with a Motorola 68000 [...] LikeLike May 12, 2023 at 2:01 pm 3. IBM PC 8088 replaced with a Motorola 68000 - TOP Show HN says: [...] Read More [...] LikeLike May 12, 2023 at 2:05 pm 4. HackerNews Zhai Yao (2023-05-12 07AM) - GPT Du Xin Wen says: [...] Lai Yuan : IBM PC 8088 replaced with a Motorola 68000 [...] LikeLike May 12, 2023 at 2:48 pm 5. IBM PC 8088 replaced with a Motorola 68000 - Quantic says: [...] Read More [...] LikeLike May 12, 2023 at 2:55 pm 6. IBM PC 8088 replaced with a Motorola 68000 - Enrichment Daily says: [...] Comments...Read More [...] LikeLike May 12, 2023 at 3:29 pm 7. HackerNews Summary (2023-05-12 07AM) - GPT News Reader says: [...] Source: IBM PC 8088 replaced with a Motorola 68000 [...] LikeLike May 12, 2023 at 3:56 pm 8. IBM PC 8088 replaced with a Motorola 68000 - Breaking News says: [...] Comments...Read More [...] LikeLike May 12, 2023 at 4:03 pm 9. IBM PC 8088 changed with a Motorola 68000 - CYBE says: [...] Read More [...] LikeLike May 12, 2023 at 4:08 pm 10. IBM PC 8088 replaced with a Motorola 68000 - Cyber Geeks Global says: [...] Comments...Read More [...] LikeLike May 12, 2023 at 8:01 pm Comments are closed. Create a free website or blog at WordPress.com. [Close and accept] Privacy & Cookies: This site uses cookies. By continuing to use this website, you agree to their use. To find out more, including how to control cookies, see here: Cookie Policy * Follow Following + [croppe] MicroCore Labs [ ] Sign me up + Already have a WordPress.com account? 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