If you define a microprocessor as being a CPU on one chip, the MP944 wasn't it.
> The CADC's MP944 chip set ran at 375 kHz, executing 9375 instructions per second. It contained six chips used to build the CADC, all based on a 20-bit fixed-point-fraction two's complement number system. They were the parallel multiplier unit (PMU) in a 28-pin DIP, the parallel divider unit (PDU) (28-pin DIP), the random-access storage (RAS) (14-pin DIP), the read-only memory (ROM) (14-pin DIP), the special logic function (SLF) (28-pin DIP), and the steering logic unit (SLU) (28-pin DIP). The complete system of 28 circuits consists of 1 PMU, 1 PDU, 1 SLF, 3 RASs, 3 SLUs, and 19 ROMs, enabled by 74,442 transistors.
There are very few engineers who wouldn't consider the POWER1 and POWER2 from IBM to be microprocessors.
They are also multi-chip units. The POWER1 was multiple chips on a PCB and the POWER2 was multiple dies on a single module (like modern AMD and Intel CPUs, but 30 years ago).
The word "microprocessor" was first used in 1968 by Viatron Computer Systems to describe its System 21, which had a multi-chip CPU spread across two boards.
A central processing unit is a term that predates using the lithographic process for microprocessors. I have documentation trying to describe the signal processing of early inertial guidance system. The documents describe all the input and output be routed to what they call a central processing unit.
This unit contained many boards but centralized the signal routing to single area and could be processed in a sequence.
I think it might be the first very advanced logic integrated circuit maybe, but if it doesn't support conditional logic and stored programs I think it's hard to call it a processor.
Processors already existed, if it doesn't do conceptually all the things a processor did, it's hard to call it one, and then you are just left with micro.
Does anyone know how many transistors were on each chip?
The complete system of 28 chips had 74,442 transistors. From that it follows that some chip had at least 74,442 / 28 = 2,659 transistors. But I am guessing some chips had less, and some chips had more. I am curious how many transistors the chips had on this computer, specifically what was the maximum amount per IC.
> The CADC's MP944 chip set ran at 375 kHz, executing 9375 instructions per second. It contained six chips used to build the CADC, all based on a 20-bit fixed-point-fraction two's complement number system. They were the parallel multiplier unit (PMU) in a 28-pin DIP, the parallel divider unit (PDU) (28-pin DIP), the random-access storage (RAS) (14-pin DIP), the read-only memory (ROM) (14-pin DIP), the special logic function (SLF) (28-pin DIP), and the steering logic unit (SLU) (28-pin DIP). The complete system of 28 circuits consists of 1 PMU, 1 PDU, 1 SLF, 3 RASs, 3 SLUs, and 19 ROMs, enabled by 74,442 transistors.