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The Rodent's PC Mark 1 was an 8 bit home microcomputer released in the Rat Republic on the 1st of August 1988. It was designed to be more of a "toy" then a real computer. By western standards this thing was HORRIBLY obsolete, with some of it's specs being "sub VIC-20 standards". Infact, due to western sanctions on the republic it was something you'd expect to have came out a decade earlier.
It was the product of the environment of late 80s early 90s Electronics Union of NIMH. Shaped from the MOUNTAINS of reversed engineered electronics that where obtained though the republic purposefully buying ewaste (which was for this EXACT reason) and the mildly successful electronic toy line the state sanctioned """"company"""" had since 1977, this computer was a culmination of both factors.
-Development-
The idea for the machine was born after some of the union's workers bringing their children in for "bring your child to work" day became obsessed with the computers there.
The Rodent's PC was envisioned to be more of an "educational" toy meant to allow the republic's rodent children to join in on the emerging computer boom in the country.
Architecturally speaking, the computer was a heavily modified 8051 microcontroller with significantly more ram, rom, speed, and peripherals.
Speaking of peripherals, one of the original designers insisted the computer must have a voice synthesizer so that it could be used without a television set. Another also insisted that the computer couldn't rely on cartridges as children loose the accessories that go with toys all the time.
The design team quickly ran into the limitations of their 8051 clone. The Harvard architecture was extremely limiting with memory management. Their wasn't enough rom to hold everything, bit banging audio was slow and resource intensive, and the chip didn't have enough ram to hold audio samples or a video buffer. The project was restarted from scratch.
The cpu (Marked "RPCM1MCU" for "Rodent's PC Mark 1 MCU") would be the core out of the 8051 clone modified to be able to read, wite, and execute on both data and instruction address spaces. The on-die rom, ram, and peripherals where removed, and in it's place an "atari 2600" style video generation. The chip also had it's clock speed bumped up SIGNIFICANTLY. The data and instruction buses where brought out for external use. Their data buses remained seperate, but both shared the same address bus to prevent the need for putting 700 pins on the package. The data bus's are 8 bit with the address bus 16 bit.
For sound a special ASIC was designed. It also included the computer's "glue logic".
The chip (Marked "RPCM1S" for "Rodent's PC Mark 1 Sound") has four voices:
-Voice 0 and 1: Dedicated to speech synthesis. It's allophones are baked into the chip's rom and cannot be changed. Both channels have a 128 byte "sentience register" to allow the chip to keep "speaking" without the need for the cpu to keep feeding it data. Each allophone "token" is 1 byte.
The "grammer" register is 4 bytes and controls if the sentence is repeated, how often, sentence length, selection between human or rodent allophones, etc.
The "accent" register is 8 bytes and allows for voice manipulation. Voice speed, pitch, etc.
-Voice 2 and 3: Square waves. Thats, about it.
Sound was the computer's BIGGEST strength, with a sizable musician community around it.
Storage wise, the computer has 4KiB of data ram, 4KiB of data rom (stored the TTS data and strings), and 8KiB of instruction rom. Both rom AND ram can be added to both address spaces via the cartridge port. A cassette interface is also available for loading and saving data.
-Performance-
Because of both data and instruction spaces where forced to use the same address bus, weird silicon-level "fuckery" was necessary in order to keep the cpu from jamming on sequential data and instruction accesses. Coupled with the cpu's requirement to generate video, performance was quite poor.
-Reception/Popularity-
Due to the price being somewhat high, it didn't sell quite nearly as well as expected. With the "Wars of the 2nd World" right next year (1989), the Rat Republic was forced to reallocate resources to military and intelligence matters, sapping resources away from the project.
The Western caused conflict also dashed all prospects of exporting the computer to other Rat Republic allies like the China, Cuba, DPRK, and other friends. Plans for exporting the computer to Africa where also scrapped.
As a result, only ~50k Rodent's PC Mark 1's where produced, with about 80% of them the rodent variant.
-Retro Revival and Reliability Issues-
Do to clever thinking, the Republic capitalized on the "retro gaming" revival of the very late 2000's and early 2010's. New old stock units of the Mark 1,2, and 3 where sold abroad, and production of the Mark 3 (which is compatible with the Mark 1) was spun back up, albeit, modernized and on much smaller process nodes. A "plug and play console" version of the computer was also made.
The originals, however, are quite unreliable. Passive components in the computer love going bad. The electrolytic capacitors love to go open, and the resistors drift.
Also, the RPCM1S chips go bad. They have LARGE dies, run HOT, moisture creeps into the chip from the poor seals on the package, and suffers from early silicon fabrication.
Other chips like the RPCM1MCU, rom, and ram also go bad, but not NEARLY as much as the RPCM1S.