AMD Semiconductor PLD Hack

AMD Semiconductor PLDs Overview

Advanced Micro Devices (AMD) was once a major force in the programmable logic industry. The foundation of its PLD business came in 1987, when AMD acquired Monolithic Memories, Inc. (MMI). MMI was the original inventor of the Programmable Array Logic (PAL) device. Through this acquisition, AMD inherited the industry-standard PAL technology and its associated patents. AMD proudly described itself as the world leader and patent-holder on the PAL device architecture. Because these legacy architectures are long out of production, reverse engineering of original PAL fuse patterns is often the only way to recover the logic for replacement or reimplementation. The company also held key patents on the extremely popular 22V10 architecture.

AMD's PLD product line began with classic bipolar TTL PAL devices. These included well-known 20-pin parts such as the PAL16L8, PAL16R4, PAL16R6, and PAL16R8. Larger 24-pin devices like the PAL20L8 and PAL20R8 families were also offered. The versatile 24-pin PAL22V10 quickly became one of the most successful PALs ever produced. On supporting programmers, a fuse-pattern dump from a known-good PAL can be read out and reused to replicate the design on equivalent parts. For even bigger designs, AMD released 28-pin parts such as the PAL24L10 and PAL24R10. The company also offered the PAL32VX10 for more advanced programmable logic requirements.

Later, AMD introduced the PALCE family, which used electrically erasable CMOS technology. The PALCE devices could be reprogrammed, giving them a major advantage over one-time-programmable bipolar parts. Key PALCE models included the PALCE16V8, PALCE20V8, and PALCE22V10. Because the CMOS cells are electrically erasable, the devices carry no encryption that would need to be cracked, which makes their logic straightforward to inspect and reuse. More advanced PALCE parts such as the PALCE24V10, PALCE26V12, and PALCE29M16 were also available.

AMD additionally developed programmable logic sequencers for state-machine applications. Notable sequencers included the PLS167, PLS168, and the CMOS PLSCE167 and PLSCE168. The Am29CPL151 and Am29CPL154 were instruction-based field-programmable controllers. For ultra-high-speed applications, AMD even produced ECL-based PAL devices, including the PAL10H20EV8 and PAL10020EV8 registered macrocells. Given their direct control over state machines, these sequencers can be disturbed by a carefully timed glitch attack on the clock line.

In the early 1990s, AMD moved into high-density CPLDs with the MACH family. The MACH 1 and MACH 2 families delivered from 900 to 3,600 gate equivalents. Popular MACH 1 and 2 models included the MACH110, MACH130, MACH210, and MACH230. The MACH 3 and MACH 4 families later added densities up to roughly 10,000 gates. The MACH 4A series scaled from 32 to 256 macrocells in both 3.3V and 5V versions. Recovering the configuration of these high-density CPLDs typically calls for firmware extraction through a programmer that understands the MACH JEDEC file format. The MACH 5 family reached densities from 128 to 512 macrocells. MACH 5 devices achieved propagation delays as fast as 5.5 nanoseconds and operating frequencies up to 182 MHz. Designers can unlock the full potential of the MACH 5 devices by using the accompanying design software to manage timing constraints.

In 1997, AMD spun off its programmable logic business into a separate company called Vantis. In 1999, Lattice Semiconductor acquired Vantis, bringing the AMD PLD legacy under the Lattice umbrella. Even after the acquisition, some engineers would hack together adapter boards to keep programming their legacy AMD PALs with modern tools.