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The KC-85 and the U880. Team members: Nadine Spörl Angela Roggan Martin Burkard Alexander Becker. KC 85/1 (Z9001). KC 85/2 (HC 900). KC 85/3. KC 85/4. Keyboard computer. Can use different OS. BASIC as programming language in ROM. 1 basic device. Basic.
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The KC-85 and the U880 Team members: Nadine Spörl Angela Roggan Martin Burkard Alexander Becker
KC 85/1 (Z9001) KC 85/2 (HC 900) KC 85/3 KC 85/4 • Keyboard • computer • Canuse • differentOS • BASIC as • programming • language in • ROM • 1 basic • device • Basic • Improvement Module Graphic Interpreter Sound Kompakt Computersystem KC 85series 1984-1990 in the GDR • Canbe • extended • 2 module • slots • Separate • keyboard
Upgrade the system RAM • plug in modules Parallelports ROM • furtherinterfaces Serialports • Add-ondevices Bus driver: extends the number of module slots by 4 Floppy disc expansion: asecond U880 system access to up to 4 floppy disc drives Operating System • CAOS (CassetteAidedOperatingSystem) Loading/storing data via tape recorder interface IDE interface
Instruction set • Exchangeinstruction • Stackinstruction • Blocklook-upandtransferinstruction • 8-bit(16-bit)loadinstruction • 8-bit (16-bit) arithmetic instruction • Branch and subroutine instruction • Rotation and shift instruction
Registers Name B,C,D,E,H,L,W,Z P (or F) R I IX,IY PC SP Type general purpose registers Processor Status register Memory Refresh register Interrupt Page address registerindex registers Program Counter register Stack Pointer register Size 8-bit 8-bit 8-bit 8-bit 16-bit 16-bit 16-bit
Flags Abbreviation N V 1 B D I Z C Type Negative flag Parity/Overflow flag UNUSED flag Break flag Decimal Node flag Interrupt Disable flag Zero flag Carry flag Location bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
Interrupts • IRQ (maskable hardware interrupts) • NMI (non-maskable hardware interrupt) • BRK (software interrupt)
AddressingModes • nine different addressing modes • Immediate addressing (8-bit) • Immediate extending addressing (16-bit) • Relative addressing (8-bit) • Extended addressing (16-bit) • Indexed addressing (16-bit + 8-bit) • Register addressing (8-bit) • Register indirect addressing (16-bit) • Bit addressing • Modified page 0 addressing
AddressingModes • Immediate addressing (8-bit) 1. The Instruction Register is loaded with the opcode 2. The KC85 is incremented 3. The data byte, which is pointed at, is read into the U880 CPU 4. The instruction is executed 5. The result is stored in the accumulator 6. The KC85 is incremented and the next instruction is loaded
AddressingModes • Immediate extending addressing • used to load 16-bit registers • instructions therefore have two data bytes • most-significant data bit is read first • stored in the most significant bit of the target register • KC85 is incremented and these steps are repeated with the least-significant bit
AddressingModes • nine different addressing modes • Immediate addressing (8-bit) • Immediate extending addressing (16-bit) • Relative addressing (8-bit) • Extended addressing (16-bit) • Indexed addressing (16-bit + 8-bit) • Register addressing (8-bit) • Register indirect addressing (16-bit) • Bit addressing • Modified page 0 addressing
Perspective/Role on the Market • Characteristics of the U880/Z80: • a mid-seventies chip • only eight bit • very slow for today's standards
Perspective/Role on the Market • Attractiveness: • very cheap • easy to handle for programmers and hardware designers • 8bit exactly match the bus width of the vast majority of • memories and peripherals on the market • the chips architecture allows easy integration with on chip peripherals • Tools are widely spread