Motorola 68040

The Motorola 68040, also referred to as the 68040 or '040, is a 32-bit processor that was produced by Motorola's Semiconductor Products Sector, superseding the Motorola 68030. The 68040 was used in the Centris, Quadra, and PowerBook 500 series. It was also used in the NeXTcube and NeXTstation computers. It was the last of the 68k processor series to be used by Apple Computer, which migrated to PowerPC processors for its Power Macintosh line.
==Features==
Introduced in 1990, the 68040 improved processor performance over the 68030 by increasing the instruction and data caches eight-fold to 4 kilobytes each. was doubled to 6 stages.68040 Microprocessor, LogicOnline. Archived 1999-04-21. However, the was known to break some older hard-coded software. This could be turned off with a software cache switch for the sake of backward compatibility, but at the expense of a 3-fold penalty in performance. A Pipelined CISC Processor: the 68040 by Leslie S. Smith. 2004.Cache is King – Enable Yours, HappyMacs. 2013-06-28.
Internal units operated at twice the speed of the external clock, so Apple and other companies sometimes marketed their 68040-based products with two clock speeds, such as 66/33MHz.Frequently Asked Questions, MicroMac. 1998-05-16.
The 68040 was available in external clock speeds up to 40MHz in a ceramic (PGA) package. However, heat became a factor in the design and a 50MHz version was cancelled. The compact (QFP) version was delayed for Apple's PowerBook 500 series and limited to 33MHz.
==Variants==
*Motorola 68LC040 - a low-cost version without a built-in floating-point unit.Technote 1011: Understanding Type 11 & No FPU Installed Errors on the Power Macintosh by Brian Bechtel, Apple Computer. 1995-10. Archived 1997-06-15. Mostly used in entry-level and portable Macintosh models. Units with mask numbers lower than 03E23G (manufactured before late 1994) contain a bug which breaks software emulating a floating-point unit, such as SoftwareFPU. These defective units were found in many early Macintosh LC 475s and Quadra 605s. Patrick Fleming of Apple Computer reportedly denied the existence of the bug, but Motorola confirmed it as bug E4 in revision 4 of their official 68LC040 errata sheet.Will Apple replace 68LC040s with CPU bug? by Daniel Hird, Google Groups. 1994-08-22.605 & Floating Point Error by Robin Macrae, Google Groups. 1994-11-18.
*Motorola 68EC040 - a lower-cost embedded version without built-in floating-point nor s. Not used by Apple in any model.
==Macintosh models with 68040 processors==
68040 (PGA) version: (with FPU)
*Macintosh Centris 660AV/Quadra 660AV (25/25 MHz)
*Macintosh Quadra 610 (25 MHz)
*Macintosh Quadra 630 (33 MHz)
*Macintosh Quadra 650 (33 MHz)
*Macintosh Quadra 700 (25 MHz)
*Macintosh Quadra 800 (33 MHz)
*Macintosh Quadra 840AV (40 MHz)
*Macintosh Quadra 900/950 (25/33 MHz)	
68LC040 (PGA) version: (no FPU)
*Macintosh Centris 610 (20 MHz)
*Macintosh Centris 650 (25 MHz)
*Macintosh Quadra 605 (25 MHz)
*Macintosh LC 475 (25 MHz)
*Macintosh LC 575 (33 MHz)
*Macintosh LC 580 (33 MHz)
*Macintosh LC 630 (33 MHz)
*Macintosh Performa 475 (25 MHz)
*Macintosh Performa 575 (33 MHz)
*Macintosh Performa 580 (33 MHz)
*Macintosh Performa 630/640 (33/33 MHz)
68040 (QFP) version: (with FPU)
*PowerBook 550c (33 MHz)	
68LC040 (QFP) version: (no FPU)
*PowerBook 190 (33 MHz)
*PowerBook 520/540 (25/33 MHz)
*PowerBook Duo 280/280c (33/33 MHz)
==References==
==See also==
*Cache Switch control panel, for managing 68040 instruction and data caches.
==External links==
*Motorola 68040 microprocessor family at CPU-World
*68040 class ICs at CPU-Collection.de
*Motorola 68040 Macs at ForeverMac (archived 2014-09-13, 2011-10-06)
**Motorola 68LC040 Macs (archived 2014-08-14, 2011-10-06)
*68LC040 CPU Bug Information at John Neil & Associates (PDF, 1999-01-30)
*CPUs: Motorola 68040 at Low End Mac (2014-06-14)
**Options for '040s by Adam Robert Guha (2000-06-05)
*MC68040: (Including EC, LC, and V) at NXP
*Motorola 68040 at Wikimedia Commons
* and at Wikipedia
**
Category:Motorola hardware