Nt1310 Unit 1 Research Paper
The first single chip CPU was the Intel 4004 invented in Nov 1971, a 4-bit processor meant for a calculator. It processed data in 4 bits, but its instructions were 8 bits long. Program and data were separate.
In 1972, Texax Instruments followed the Intel 4004/4040 closely with the 4-bit TMS 1000, which was the first microprocessor to include enough RAM, and space for a program ROM, to allow it to operate without multiple external support chips. It also featured an innovative feature to add custom instructions to the CPU.
The 8080 was the successor to the 8008 in April 1972. While the 8008 had 14 bit PC and addressing, the 8080 had a 16 bit address bus and an 8 bit data bus. Internally it had seven 8 bit registers, a 16 bit stack pointer to memory which replaced the 8 level internal stack of the 8008, and a 16 bit program counter. It also had several I/O ports - 256 of them, …show more content…
While the 8008 had 14 bit PC and addressing, the 8080 had a 16 bit address bus and an 8 bit data bus. Internally it had seven 8 bit registers, a 16 bit stack pointer to memory which replaced the 8 level …show more content…
It also used 8 bit data and 16 bit addressing, and could execute all of the 8080 (but not 8085) op codes, but included 80 more, instructions. The register set was doubled, with two banks of data registers that could be switched between. This allowed fast operating system or interrupt context switches. The Z-80 also added two index registers and 2 types of relocatable vectored interrupts. The thing that really made the Z-80 popular in designs was the memory interface - the CPU generated its own RAM refresh signals, which meant easier design and lower system cost, the deciding factor in its selection for the TRS-80 Model 1. That and its 8080 compatibility, and CP/M, the first standard microprocessor operating system, made it the first choice of many
In 1972, Texax Instruments followed the Intel 4004/4040 closely with the 4-bit TMS 1000, which was the first microprocessor to include enough RAM, and space for a program ROM, to allow it to operate without multiple external support chips. It also featured an innovative feature to add custom instructions to the CPU.
The 8080 was the successor to the 8008 in April 1972. While the 8008 had 14 bit PC and addressing, the 8080 had a 16 bit address bus and an 8 bit data bus. Internally it had seven 8 bit registers, a 16 bit stack pointer to memory which replaced the 8 level internal stack of the 8008, and a 16 bit program counter. It also had several I/O ports - 256 of them, …show more content…
While the 8008 had 14 bit PC and addressing, the 8080 had a 16 bit address bus and an 8 bit data bus. Internally it had seven 8 bit registers, a 16 bit stack pointer to memory which replaced the 8 level …show more content…
It also used 8 bit data and 16 bit addressing, and could execute all of the 8080 (but not 8085) op codes, but included 80 more, instructions. The register set was doubled, with two banks of data registers that could be switched between. This allowed fast operating system or interrupt context switches. The Z-80 also added two index registers and 2 types of relocatable vectored interrupts. The thing that really made the Z-80 popular in designs was the memory interface - the CPU generated its own RAM refresh signals, which meant easier design and lower system cost, the deciding factor in its selection for the TRS-80 Model 1. That and its 8080 compatibility, and CP/M, the first standard microprocessor operating system, made it the first choice of many