--- title: Tesla PMI-80 categories: - Computers types: - Home Computer origins: - Czechoslovakia cpus: - TESLA MHB 8080 params: name: PMI-80 image: /media/museum/photos/tesla_pmi80_system_s2.jpg logo: /media/museum/logos/tesla_pmi80_logo1.gif company: /companies/tesla company_name: Tesla specs: - label: NAME value: PMI-80 - label: MANUFACTURER value: Tesla - label: TYPE value: Home Computer - label: ORIGIN value: Czechoslovakia - label: BUILT IN LANGUAGE value: Machine language hexadecimal monitor - label: KEYBOARD value: 25 key calculator type - Hexadecimal and function keys - label: CPU value: TESLA MHB 8080 (Intel 8080 clone) - label: SPEED value: 1 MHz - label: CO-PROCESSOR value: None - label: RAM value: 1 KB - label: ROM value: 1 KB - label: TEXT MODES value: 9 digit, 7 segment, diode calculator type - label: I/O PORTS value: DIN 5-pin Power - DIN 5-pin analog I/O to tape - - label: POWER SUPPLY value: External power supply unit, +5V / -5V / +12V - label: PERIPHERALS value: Additional ROM and I/O chip sockets tabs: - photos - adverts - connectors photos: - title: MAIN BOARD subtitle: '' text: |- **(1)** Tape recorder DIN socket\ **(2)** MHB 8080 microprocessor\ **(3)** MH 8228 (Intel 8228 clone) - MicroBus controler, converts CPU signals into I/O, MEM, R/W signals\ **(4)** MHB 8255 (Intel 8255 clone) - main I/O chip, 3x8-bit I/O channels, 1 channel for user, 2 channels for keyboard & display\ **(5)** Second optional 8255 offering three additional I/O channels\ **(6)** ROM chip holding the MONITOR program\ **(7)**MH 8224 clock generator and MH 3205 memory controller\ **(8)** Two MHB 2114 (Intel 1k \* 4-bit 2114 clone) RAM chips holding the 1 KB user RAM\ **(9)** Optional I/O card connectors An expansion bus is also located between the microprocessor and the ROM chip. image: /media/museum/photos/tesla_pmi80_system_s1.jpg - title: COMPLETE SYSTEM subtitle: '' text: Thanks to **Horymir Marek** image: /media/museum/photos/tesla_pmi80_system_s3.jpg - title: PMI-80 CASE subtitle: '' text: '' image: /media/museum/photos/tesla_pmi80_case_s1.jpg - title: CHIPS CLOSE-UP subtitle: '' text: |- CPU, I/O, ROM and RAM chips. Thanks to **Horymir Marek** image: /media/museum/photos/tesla_pmi80_boardcloseup_s2.jpg - title: KEYBOARD subtitle: '' text: '' image: /media/museum/photos/tesla_pmi80_keyboard_s1.jpg - title: DISPLAY subtitle: '' text: Calculator type diodes display image: /media/museum/photos/tesla_pmi80_display_s1.jpg - title: 'DISPLAY #2' subtitle: '' text: |- When the computer starts, it displays this message. Thanks to **Horymir Marek** image: /media/museum/photos/tesla_pmi80_displight_s1.jpg - title: PMI-80 LOGO subtitle: '' text: '' image: null - title: I/O CARD subtitle: '' text: This card displays each bit of the data bus. It also has a digital to analog converter which allow 0V to 12V output with 256 steps. The max voltage can be adjusted, between 0 and 12V, thanks to the variable resistor. image: /media/museum/photos/tesla_pmi80_iocard_s1.jpg - title: MANUALS subtitle: '' text: |- The manuals were actualy a complete course on each chip which make up the computer. Thanks to **Horymir Marek** image: /media/museum/photos/tesla_pmi80_manuals_s1.jpg adverts: - title: DIAGRAMS subtitle: '' text: |- PMI-80 diagram located in the case cover.\ If you are interested in more diagrams of the PMI-80, dowload this zipped file holding three diagrams of the whole system. image: /media/museum/pubs/tesla_pmi80_casecover_s1.jpg connectors: - title: CHIPS ARRANGEMENT subtitle: '' text: Thanks to **Horymir Marek** image: /media/museum/connectors/tesla_pmi80_diagram_s1.jpg - title: CPU subtitle: '' text: Thanks to **Horymir Marek** image: /media/museum/connectors/tesla_pmi80_diagram_s2.jpg - title: CONNECTORS subtitle: '' text: Thanks to **Horymir Marek** image: /media/museum/connectors/tesla_pmi80_diagram_s3.jpg - title: KEYBOARD, TAPE INTERFACE & POWER REGULATION subtitle: '' text: Thanks to **Horymir Marek** image: /media/museum/connectors/tesla_pmi80_diagram_s4.jpg comments: - author: Nyxt date: Tuesday 8th March 2022 text: this is basic - author: Nyxt date: Tuesday 8th March 2022 text: Did you lose you mind, Elon Musk? - author: belgium4 (Belgium) date: Monday 12th September 2011 text: |- I have one in my collection.\ I''m glad that I''ve found some info aroung this single board computer.\ Thnx\ Michel - author: Roman Kiss (Slovakia) date: Sunday 10th June 2007 text: Thanks for remember me this baby. It was a long time ago, in the big garage Tesla. - author: Gergely Takacs (Slovakia) date: Wednesday 18th May 2005 text: Yes there is an emulator for PMI80... Altough I've heard there are some problems with it under W.XP, I can work with itt allright. The interface is pretty darn simple (just as probably the PMI80 was)... - author: Linkman (Slovak Republic) date: Saturday 23rd April 2005 text: Is extra emlator for PMI-80? - author: Blackhead (Prague) date: Tuesday 25th May 2004 text: If you want to know enything about it ask here. I'll answer it! oc_id: 1016 source: url: https://web.archive.org/web/20230606190802/http://www.old-computers.com/museum/computer.asp?c=1016 date: '2023-06-06' --- The PMI was used for learning programing machine code in Czech and Slovakian polytechnic university from 1982 year. It was developed and manufactured in Tesla Piestany factory which core business was to produceo active components like diode, transistor and integrated ciruits, including the MHB 8080A CPU and chip from his family. It was a basic system, enclosed in a plastic case and precisely based on the MHB 8080A, a Tesla version the 8080 processor. It had minimal ROM, RAM and I/O capabilities, but enough in schools, to enter, study and run small programs. Thanks to **Jiri Cernohlavek**, from Czech Republic, for information and pictures. --- **Martin Bruno** remembers:\ I used this computer when I was attending Industrial College Of Electrical Engineering in Eastern Slovakia, town of Michalovce at second class in 1994/95 and this computer was widely used at Slovakian technical schools for learning machine code of 8080 processor.\ It was a bit complicated because you had to write program in hex form. Actually it was computer but practically not for home use nor for some entertainment... it was a good form how to scare people about machine code programming :-)\ I must to thank my home computer [Didaktik M](/museum/didaktik-m/) at that time that I learned machine code resp. assembler in much more comfortable way :-) **Dan Handenberg** adds:\ The computer was originally designed to control printing machines, but the processing was too slow to transfer information fast enough to the peripherals.
We need more info about this computer ! If you designed, used, or have more info about this system, please send us pictures or anything you might find useful.