Intel 8085: Difference between revisions
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(Created page with "{{Infobox CPU|name=Intel 8085|produced-start=March 1976|manuf1=Intel|slowest=3|data-width=8 bits|address-width=16 bits|slow-unit=MHz|fastest=6|fast-unit=MHz|instructions=Intel 8080|predecessor=Intel 8080|successor=Intel 8086}} The Intel 8085 is a 8-bit microprocessor. Category:Microprocessors Category:Intel Microprocessors Category:8-bit microprocessors") |
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{{Infobox CPU|name=Intel 8085|produced-start=March 1976|manuf1=[[Intel]]|slowest=3|data-width=8 bits|address-width=16 bits|slow-unit=MHz|fastest=6|fast-unit=MHz|instructions=[[Intel 8080 instruction set|Intel 8080]]|predecessor=[[Intel 8080]]|successor=[[Intel 8086]]}} | {{Infobox CPU|name=Intel 8085|produced-start=March 1976|manuf1=[[Intel]]|slowest=3|data-width=8 bits|address-width=16 bits|slow-unit=MHz|fastest=6|fast-unit=MHz|instructions=[[Intel 8080 instruction set|Intel 8080]]|predecessor=[[Intel 8080]]|successor=[[Intel 8086]]}} | ||
The [[Intel]] 8085 is | The [[Intel]] 8085 is an [[8-bit computing|8-bit]] [[microprocessor]] and successor of the [[Intel 8080]]. The final "5" in the part number indicates that it uses only a single +5V power rail. The processor itself remains binary compatible with the 8080 [[Instruction set architecture|ISA]], only adding two additional instructions. | ||
== Design == | |||
As the successor to the [[Intel 8080]], the 8085 simplified the design to make it easier to use by removing the multiplexing of data and state signals, instead using the lower 8-bits of the address bus. Additionally, unlike it's predecessor, the 8080, the 8085 uses only a single +5V rail for power. | |||
===Registers=== | |||
{| class="infobox" style="font-size:88%;width:34em;" | |||
|+ Intel 8080 registers | |||
|- | |||
| style="text-align:center;"| <sup>1</sup><sub>5</sub> | |||
| style="text-align:center;"| <sup>1</sup><sub>4</sub> | |||
| style="text-align:center;"| <sup>1</sup><sub>3</sub> | |||
| style="text-align:center;"| <sup>1</sup><sub>2</sub> | |||
| style="text-align:center;"| <sup>1</sup><sub>1</sub> | |||
| style="text-align:center;"| <sup>1</sup><sub>0</sub> | |||
| style="text-align:center;"| <sup>0</sup><sub>9</sub> | |||
| style="text-align:center;"| <sup>0</sup><sub>8</sub> | |||
| style="text-align:center;"| <sup>0</sup><sub>7</sub> | |||
| style="text-align:center;"| <sup>0</sup><sub>6</sub> | |||
| style="text-align:center;"| <sup>0</sup><sub>5</sub> | |||
| style="text-align:center;"| <sup>0</sup><sub>4</sub> | |||
| style="text-align:center;"| <sup>0</sup><sub>3</sub> | |||
| style="text-align:center;"| <sup>0</sup><sub>2</sub> | |||
| style="text-align:center;"| <sup>0</sup><sub>1</sub> | |||
| style="text-align:center;"| <sup>0</sup><sub>0</sub> | |||
| ''(bit position)'' | |||
|- 16 | |||
|colspan="17" | '''Main registers''' <br/> | |||
|- style="background:silver;color:black" | |||
| style="text-align:center;" colspan="8"| A | |||
| style="text-align:center;background:#DDD" colspan="8"| Flags | |||
| style="width:auto; background:white; color:black;"| '''P'''rogram '''S'''tatus '''W'''ord | |||
|- style="background:silver;color:black" | |||
| style="text-align:center;" colspan="8"| B | |||
| style="text-align:center;" colspan="8"| C | |||
| style="background:white; color:black;"| '''B''' | |||
|- style="background:silver;color:black" | |||
| style="text-align:center;" colspan="8"| D | |||
| style="text-align:center;" colspan="8"| E | |||
| style="background:white; color:black;"| '''D''' | |||
|- style="background:silver;color:black" | |||
| style="text-align:center;" colspan="8"| H | |||
| style="text-align:center;" colspan="8"| L | |||
| style="background:white; color:black;"| '''H''' (indirect address) | |||
|- | |||
|colspan="17" | '''Index registers''' <br/> | |||
|- style="background:silver;color:black" | |||
| style="text-align:center;" colspan="16"| SP | |||
| style="background:white; color:black;"| '''S'''tack '''P'''ointer | |||
|- | |||
|colspan="17" | '''Program counter''' <br/> | |||
|- style="background:silver;color:black" | |||
| style="text-align:center;" colspan="16"| PC | |||
| style="background:white; color:black;"| '''P'''rogram '''C'''ounter | |||
|- | |||
|colspan="17" | '''Status register''' | |||
|- style="background:silver;color:black" | |||
| style="text-align:center; background:white" colspan="8" | | |||
| style="text-align:center;"| [[Sign flag|S]] | |||
| style="text-align:center;"| [[Zero flag|Z]] | |||
| style="text-align:center;"| – | |||
| style="text-align:center;"| [[Half-carry flag|AC]] | |||
| style="text-align:center;"| – | |||
| style="text-align:center;"| [[Parity flag|P]] | |||
| style="text-align:center;"| – | |||
| style="text-align:center;"| [[Carry flag|C]] | |||
| style="background:white; color:black" | Flags | |||
|} | |||
There are seven 8-bit general [[Processor register|registers]] ('''A''', '''B''', '''C''', '''D''', '''E''', '''H''' and '''L''') and one status register, where A is the primary 8-bit accumulator. The other six registers can be used as either individual 8-bit registers or in three 16-bit register pairs ('''BC''', '''DE''' and '''HL''', referred to as '''B''', '''C''' and '''H''' in Intel documentation) depending on the particular instruction. Some instructions also enable the HL register pair to be used as a (limited) 16-bit accumulator. A pseudo-register '''M''', which refers to the dereference memory location pointed to by HL, can be used almost anywhere other registers can be used. The 8085 has a 16-bit [[stack pointer]] ('''SP''') to memory and a 16-bit program counter ('''PC'''). | |||
[[Category:Microprocessors]] | [[Category:Microprocessors]] | ||
[[Category:Intel Microprocessors]] | [[Category:Intel Microprocessors]] | ||
[[Category:8-bit microprocessors]] | [[Category:8-bit microprocessors]] | ||
Latest revision as of 05:56, 31 December 2023
| General information | |
|---|---|
| Launched | March 1976 |
| Common manufacturer(s) | |
| Performance | |
| Max. CPU clock rate | 3 MHz to 6 MHz |
| Data width | 8 bits |
| Address width | 16 bits |
| Architecture and classification | |
| Instructions | Intel 8080 |
| History | |
| Predecessor(s) | Intel 8080 |
| Successor(s) | Intel 8086 |
The Intel 8085 is an 8-bit microprocessor and successor of the Intel 8080. The final "5" in the part number indicates that it uses only a single +5V power rail. The processor itself remains binary compatible with the 8080 ISA, only adding two additional instructions.
Design
As the successor to the Intel 8080, the 8085 simplified the design to make it easier to use by removing the multiplexing of data and state signals, instead using the lower 8-bits of the address bus. Additionally, unlike it's predecessor, the 8080, the 8085 uses only a single +5V rail for power.
Registers
| 15 | 14 | 13 | 12 | 11 | 10 | 09 | 08 | 07 | 06 | 05 | 04 | 03 | 02 | 01 | 00 | (bit position) |
| Main registers | ||||||||||||||||
| A | Flags | Program Status Word | ||||||||||||||
| B | C | B | ||||||||||||||
| D | E | D | ||||||||||||||
| H | L | H (indirect address) | ||||||||||||||
| Index registers | ||||||||||||||||
| SP | Stack Pointer | |||||||||||||||
| Program counter | ||||||||||||||||
| PC | Program Counter | |||||||||||||||
| Status register | ||||||||||||||||
| S | Z | – | AC | – | P | – | C | Flags | ||||||||
There are seven 8-bit general registers (A, B, C, D, E, H and L) and one status register, where A is the primary 8-bit accumulator. The other six registers can be used as either individual 8-bit registers or in three 16-bit register pairs (BC, DE and HL, referred to as B, C and H in Intel documentation) depending on the particular instruction. Some instructions also enable the HL register pair to be used as a (limited) 16-bit accumulator. A pseudo-register M, which refers to the dereference memory location pointed to by HL, can be used almost anywhere other registers can be used. The 8085 has a 16-bit stack pointer (SP) to memory and a 16-bit program counter (PC).