Editing Motorola 68000 (section)

==Variants==
In 1982, the 68000 received a minor update to its [[instruction set architecture]] (ISA) to support [[virtual memory]] and to conform to the [[Popek and Goldberg virtualization requirements]]. The updated chip is called the [[Motorola 68010|68010]].<ref>{{cite book|url=https://books.google.com/books?id=m1PKCQAAQBAJ&pg=PA53|title=Cloud Computing: Business Trends and Technologies|last1=Faynberg|first1=Igor|last2=Lu|first2=Hui-Lan|last3=Skuler|first3=Dor|publisher=[[Wiley (publisher)|Wiley]]|date=2016|access-date=2022-07-29|page=53|isbn=978-1-118-50121-4|archive-date=July 29, 2022|archive-url=https://web.archive.org/web/20220729234027/https://books.google.com/books?id=m1PKCQAAQBAJ&pg=PA53|url-status=live}}</ref> It also adds a new "loop mode" which speeds up small loops, and increases overall performance by about 10% at the same clock speeds. A further extended version, which exposes 31&nbsp;bits of the address bus, was also produced in small quantities as the [[Motorola 68012|68012]].

To support lower-cost systems and control applications with smaller memory sizes, Motorola introduced the 8-bit compatible [[Motorola 68008|MC68008]], also in 1982. This is a 68000 with an 8-bit data bus and a smaller (20-bit) address bus. After 1982, Motorola devoted more attention to the [[Motorola 68020|68020]] and [[Motorola 88000|88000]] projects.

===Second-sourcing===
[[File:KL Hitachi HD68000.jpg|thumb|[[Hitachi]] HD68000]]
[[File:KL Thomson TS68000.jpg|thumb|Thomson TS68000]]

Several other companies were [[Second source|second-source]] manufacturers of the HMOS 68000.  These included [[Hitachi]] (HD68000), who shrank the feature size to 2.7&nbsp;μm for their 12.5&nbsp;MHz version,<ref name="easy68k" /> [[Mostek]] (MK68000), [[Rockwell International|Rockwell]] (R68000), [[Signetics]] (SCN68000), [[Thomson-CSF|Thomson]]/[[STMicroelectronics|SGS-Thomson]] (originally EF68000 and later TS68000), and [[Toshiba]] (TMP68000). Toshiba was also a second-source maker of the CMOS 68HC000 (TMP68HC000).

Encrypted variants of the 68000, being the Hitachi FD1089 and FD1094, store decryption keys for opcodes and opcode data in battery-backed memory and were used in certain Sega arcade systems including [[System 16]] to prevent piracy and illegal bootleg games.<ref>{{cite web|url=http://segaretro.org/FD1094|title=FD1094 – Sega Retro|website=segaretro.org|date=19 October 2017|access-date=October 27, 2015|archive-date=September 28, 2013|archive-url=https://web.archive.org/web/20130928185644/http://segaretro.org/FD1094|url-status=live}}</ref>

===CMOS versions===
[[File:Motorola MC68HC000LC8-2413.jpg|thumb|Motorola MC68HC000LC8]]

The 68HC000, the first [[CMOS]] version of the 68000, was designed by Hitachi and jointly introduced in 1985.<ref>[https://select.nytimes.com/gst/abstract.html?res=F00612F73C5D0C728EDDA00894DD484D81 "Company Briefs"] {{Webarchive|url=https://web.archive.org/web/20071114063028/http://select.nytimes.com/gst/abstract.html?res=F00612F73C5D0C728EDDA00894DD484D81 |date=November 14, 2007 }}, The New York Times, September 21, 1985, available from TimesSelect (subscription).</ref> Motorola's version is called the MC68HC000, while Hitachi's is the HD68HC000. The 68HC000 offers speeds of 8–20&nbsp;MHz. Except for using CMOS circuitry, it behaved identically to the HMOS MC68000, but the change to CMOS greatly reduced its power consumption. The original HMOS MC68000 consumed around 1.35&nbsp;[[watt]]s at an ambient temperature of 25&nbsp;[[Celsius|°C]], regardless of clock speed, while the MC68HC000 consumed only 0.13&nbsp;watts at 8&nbsp;MHz and 0.38&nbsp;watts at 20&nbsp;MHz. (Unlike CMOS circuits, HMOS still draws power when idle, so power consumption varies little with clock rate.) Apple selected the 68HC000 for use in the [[Macintosh Portable]] and [[PowerBook 100]].

Motorola replaced the MC68008 with the MC68HC001 in 1990.<ref>{{cite magazine|title=68HC001 obsoletes 68008|magazine=[[Microprocessor Report]]|date=June 20, 1990}}</ref> This chip resembles the 68HC000 in most respects, but its data bus can operate in either 16-bit or 8-bit mode, depending on the value of an input pin at reset. Thus, like the 68008, it can be used in systems with cheaper 8-bit memories.

The later evolution of the 68000 focused on more modern [[embedded control]] applications and on-chip peripherals. The '''68EC000''' chip and SCM68000 core remove the M6800 peripheral bus, and exclude the MOVE from SR instruction from user mode programs, making the 68EC000 and 68SEC000 the only 68000 CPUs not 100% object code compatible with previous 68000 CPUs when run in User Mode. When run in Supervisor Mode, there is no difference.<ref>{{cite magazine|title=Motorola streamlines 68000 family; "EC" versions of 68000, '020, '030, and '040, plus low-end 68300 chip"|magazine=Microprocessor Report|date=April 17, 1991}}</ref> In 1996, Motorola updated the standalone core with fully static circuitry, drawing only 2&nbsp;[[μW]] in low-power mode, calling it the MC68SEC000.<ref>{{cite press release |url=http://mot-sps.com/press/html/PR961118B.html |title=Motorola reveals MC68SEC000 processor for low power embedded applications |date=November 18, 1996 | archive-url=https://web.archive.org/web/19970328231731/http://mot-sps.com/press/html/PR961118B.html |archive-date=March 28, 1997 | publisher=Motorola}}</ref>

Motorola ceased production of the HMOS MC68000, as well as the MC68008, MC68010, MC68330, and MC68340 in on June 1, 1996,<ref>{{cite journal|url=https://www.datasheetarchive.com/pdf/download.php?id=f289b43a955580968b84c0f71b9c1bbf874b61|format=PDF|title=HIPPO Q495|journal=High-Performance Internal Product Portfolio Overview|publisher=[[Motorola]]|date=Fourth Quarter 1995|issue=10|access-date=July 29, 2022|archive-date=September 14, 2022|archive-url=https://web.archive.org/web/20220914195057/https://www.datasheetarchive.com/pdf/download.php?id=f289b43a955580968b84c0f71b9c1bbf874b61|url-status=live}}</ref><ref>[http://groups.google.com/group/comp.sys.m68k/browse_frm/thread/ab9a8520ee794d85/cedb5e4f449f346c comp.sys.m68k Usenet posting] {{Webarchive|url=https://web.archive.org/web/20071114093111/http://groups.google.com/group/comp.sys.m68k/browse_frm/thread/ab9a8520ee794d85/cedb5e4f449f346c |date=November 14, 2007 }}, May 16, 1995; also see other posts in thread. The end-of-life announcement was in late 1994; according to standard Motorola end-of-life practice, final orders would have been in 1995, with final shipments in 1996.</ref> but its spin-off company [[Freescale Semiconductor]] (now [[NXP Semiconductors|NXP]]) was still producing the MC68HC000, MC68HC001, MC68EC000, and MC68SEC000, as well as the MC68302 and MC68306 microcontrollers and later versions of the [[Freescale DragonBall|DragonBall]] family. The 68000's architectural descendants, the [[68000 series|680x0]], [[CPU32]], and [[Freescale ColdFire|Coldfire]] families, were also still in production. More recently, with the Sendai fab closure in 2010, all 68HC000, 68020, 68030, and 68882 parts have been discontinued, leaving only the 68SEC000 in production.<ref>{{cite web|url=http://cache.freescale.com/files/shared/doc/pcn/PCN13644D.htm|title=Freescale 150mm Sendai Fab Closure-General Product Discontinuance|date=November 24, 2010|access-date=March 9, 2014|archive-date=March 9, 2014|archive-url=https://web.archive.org/web/20140309084150/http://cache.freescale.com/files/shared/doc/pcn/PCN13644D.htm|url-status=live}}</ref>

In 2024, [[Rochester Electronics]] was licensed by NXP to continue producing the 68HC000. Both the physical design and test program were transferred to Rochester from NXP in order to continue to supply an authorized source to the market. Rochester Electronics' version of the 68HC000 uses a product clone of the J82M [[Photomask|mask set]] (also known as the TSC6), which was the last mask set used by Motorola for the 68HC000.<ref>{{Cite web|url=https://www.nxp.jp/docs/en/product-change-notice/PCN3666.html|title=Introduction of KLM as Qualified Test Site for 68060|website=www.nxp.jp|access-date=April 2, 2025}}</ref>

===As a microcontroller core===
Since being succeeded by "true" 32-bit microprocessors, the 68000 is used as the core of many [[microcontroller]]s. In 1989, Motorola introduced the [[Freescale 683XX|MC68302]] communications processor.<ref>{{cite magazine |date=November 1, 1989 |url=http://www.accessmylibrary.com/coms2/summary_0286-9209083_ITM |title=Multiprotocol processor marries 68000 and RISC |magazine=ESD: The Electronic System Design Magazine |via=AccessMyLibrary}}</ref>