SAPI-1

The SAPI-1 was a computer produced in the former Czechoslovakia by Tesla since 1980.

It was designed by Eduard Smutný (hardware) and his brother Tomas Smutný (software), and based on the Intel 8080/2 MHz clone (and later Z80). The SAPI-86 was also developed as a 8086 clone of the PC.

The SAPI-1 had a modular construction with modules:

• JPR-1 - processor board based on MHB8080 processor, 1 KB SRAM, 4 KB ROM modules and 6 IO ports
• ARB-1 - bus unit
• JZS-1 - power supply with rack
• ANK-1 - non smart, no ergonomic membrane keyboard (compatible with Sinclair ZX-80 and ZX-81)
• REM-1 - extension board with EPROM and SRAM modules
• AND-1 - alfanumeric video adapter, 40 columns x 24 rows, black and white with 2 KBytes of video buffer
• RAM-1 - board of 32 KB of dynamic RAM
• DSM-1 - modem and serial interface (based on MHB 1012 UART) used to communication with tape recorder
• BDK-1 - universal developer board
• DPP-1 - parallel port board (based on two MHB 8255 chips)
• DGD-1 - graphic video adapter - requires second monitor, cannot output to monitor connected to AND-1
• RPD-1 - floppy disk controller, due to its complexity was built on two boards connected by cable. This came very late.

3 versions of SAPI-1 were produced:

• SAPI-1 ZPS 1 (základní průmyslová sestava - basic industrial set):

OS (integer Micro-Basic) was stored in ROM, as well as simple machine code monitor, tape was used as main storage device.

• SAPI-1 ZPS 2:

OS (MIKOS - mikro kazetový operační systém, micro cassette operating system) with better machine code monitor was stored in ROM, any other programming language was loaded from tape.

• SAPI-1 ZPS 3:

ROM contains CP/M booting sequence, CP/M is booting from 8" Shugart floppy disk drives. Position of VideoRAM was moved from 3800 to E000 to allow CP/M running. The "Z" version of SAPI-1 ZPS 3 used Z-80 processor clone instead of 8080 clone.