Gregory's ServerThe Intel 2920 was designed for a wide range of analog applications from filters to speech synthesis to missile guidance. It was created by Ted Hoff (one of the inventors of the microprocessor) and Marshall Townsend. Although the chip was called "Product of the Year" by the magazine Electronic Products, it was buggy and not a market success. 3/7
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 The 2920 had four analog inputs and eight analog outputs. The digital-to-analog converter (DAC) was unusual and large: a chain of 256 tiny resistors arranged in a grid. Energizing two digital switches (i.e. transistors) provided a tap for the desired voltage. Analog-to-digital conversion was built on top of the DAC, "guessing" one bit at a time. 5/7 The chip didn't have multiplication or division in hardware, but it had a barrel shifter to quickly multiply or divide by a power of 2. The compiler for the chip is very unusual. Instead of normal code, you define poles and zeros and the compiler builds the code to implement the desired filter. 6/7 Thanks to @tubetime for providing the chip. |
Interesting chip art on the Intel 2920: a cactus on the die, maybe because Intel opened a site in Arizona that year. 4/7