CPU of the Day: Motorola MC68040VL

Motorola MC68040VL

A month or so ago a friend was opening up a bunch of unmarked packages, and taking die photos and came across an interesting Motorola.  The die looked familiar, but at the same time different.  The die was marked 68040VL, and appeared to be smaller version of the 68040V.  The Motorola 68040V is a 3.3V static design of the Motorola MC68LC040 (It has dual MMUs but lacks the FPU of the 68040).  The 68040V was made on a 0.5u process and introduced in 1995.  Looking closely at the mask revealed the answer, in the form of 4 characters. F94E

Motorola Mask F94E – COLDFIRE 5102

Motorola uses mask codes for nearly all of their products, in many ways these are similar to Intel’s sspecs, but they are more closely related to actual silicon mask changes in the device.  Multiple devices may use the same mask/mask code just with different features enabled/disabled.  The Mask code F94E is that of the first generation Motorola COLDFIRE CPU, the MCF5102.  The COLDFIRE was the replacement for the Motorola 68k line, it was designed to be a 32-bit VL-RISC processor, thus the name 68040VL for VL-RISC. .  VL-RISC architectures support fixed length instruction (like a typical RISC) but also support variable length instructions like a traditional CISC processor.  This allows a lot more code flexibility and higher code density.  While this may be heresy to RISC purists it has become rather common.  The ST Transputer based ST20 core is a VL-RISC design, as is the more modern RISC-V architecture.  The COLDFIRE 5102 also had another trick, or treat up its sleeve.  It could execute 68040 code.

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