300px, Image of the internals of a Commodore 64 showing the 6510 CPU (40-pin DIP, lower left). The chip on the right is the 6581 SID. The production week/year (WWYY) of each chip is given below its name. The MOS Technology 6510 is an

8-bit In computer architecture, 8-bit Integer (computer science), integers or other Data (computing), data units are those that are 8 bits wide (1 octet (computing), octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) arc ...

microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...

MOS Technology MOS Technology, Inc. ("MOS" being short for Metal Oxide Semiconductor), later known as CSG (Commodore Semiconductor Group) and GMT Microelectronics, was a semiconductor design and fabrication company based in Audubon, Pennsylvania. It is mo ...

. It is a modified form of the very successful

6502 The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small te ...

. The 6510 is widely used in the

Commodore 64 The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness ...

(C64) home computer and its variants. The primary change from the 6502 is the addition of an 8-bit general purpose I/O port, although 6 I/O pins are available in the most common version of the 6510. In addition, the address bus can be made tristate and the CPU can be halted cleanly.

Use

In the C64, the extra I/O pins of the processor are used to control the computer's

memory map In computer science, a memory map is a structure of data (which usually resides in memory itself) that indicates how memory is laid out. The term "memory map" can have different meanings in different contexts. *It is the fastest and most flexible ...

bank switching Bank switching is a technique used in computer design to increase the amount of usable memory beyond the amount directly addressable by the processor instructions. It can be used to configure a system differently at different times; for example ...

, and for controlling three of the four signal lines of the Datasette tape recorder (the electric motor control, key-press sensing and write data lines; the read data line went to another I/O chip). It is possible, by writing the correct

bit pattern The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented a ...

to the processor at address $01, to completely expose almost the full 64 KB of

RAM Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch * ...

in the C64, leaving no

ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...

or I/O hardware exposed except for the processor I/O port itself and its data directional register at address $00.

Variants

MOS 8500

In 1985, MOS produced the 8500, an

HMOS In integrated circuits, depletion-load NMOS is a form of digital logic family that uses only a single power supply voltage, unlike earlier NMOS (n-type metal-oxide semiconductor) logic families that needed more than one different power supply v ...

version of the 6510. Other than the process modification, it is virtually identical to the NMOS version of the 6510. The 8500 was originally designed for use in the modernised C64, the C64C. However, in 1985, limited quantities of 8500s were found on older NMOS-based C64s. It finally made its official debut in 1987, appearing in a motherboard using the new 85xx HMOS chipset.

MOS 7501/8501

The 7501/8501 variant of the 6510 was introduced in 1984.Hardware – MOS 7501/8501
/ref> Compared to the 6510, this variant extends the number of I/O port pins from 6 to 8, but omits the pins for non-maskable interrupt and clock output. It is used in Commodore's C16, C116 and Plus/4 home computers, where its I/O port controls not only the Datasette but also the CBM Bus interface. The main difference between 7501 and 8501 CPUs is that they were manufactured with slightly different processes: 7501 was manufactured with HMOS-1 and 8501 with HMOS-2.

MOS 8502

The 2

MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...

-capable 8502 variant is used in the

Commodore 128 The Commodore 128, also known as the C128, C-128, C= 128,The "C=" represents the graphical part of the logo. is the last 8-bit home computer that was commercially released by Commodore Business Machines (CBM). Introduced in January 1985 at the ...

. All these CPUs are

opcode In computing, an opcode (abbreviated from operation code, also known as instruction machine code, instruction code, instruction syllable, instruction parcel or opstring) is the portion of a machine language instruction that specifies the operat ...

compatible (including undocumented opcodes).

MOS 6510T

The

Commodore 1551 The Commodore 1551 (originally introduced as the SFS 481) is a floppy disk drive for the Commodore Plus/4 home computer. It resembles a charcoal-colored Commodore 1541 and plugs into the cartridge port, providing faster access than the C64/1 ...

disk drive (for the

Commodore Plus/4 The Commodore Plus/4 is a home computer released by Commodore International in 1984. The "Plus/4" name refers to the four-application ROM resident office suite (word processor, spreadsheet, database, and graphing); it was billed as "the produ ...

) uses the 6510T, a version of the 6510 with eight I/O lines. The NMI and RDY signals are not available.

References

External links

MOS 6510 datasheet (GIF format, zipped)

MOS 6510 datasheet (PDF format)

MOS 6510 datasheet (Nov. 1982, PDF format)

Computer Emulation Resources
(includes downloadable source code for 6502) * {{DEFAULTSORT:Mos Technology 6510 65xx microprocessors MOS Technology microprocessors Commodore 64 8-bit microprocessors

Use