300px, 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 integers or other data units are those that are 8 bits wide (1 octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data bu ...

microprocessor A microprocessor is a computer processor (computing), processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, a ...

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 ...

. It is a modified form of the very successful 6502. The 6510 is widely used in the

Commodore 64 The Commodore 64, also known as the C64, is an 8-bit computing, 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 ...

(C64)

home computer Home computers were a class of microcomputers that entered the market in 1977 and became common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a s ...

and its variants. It is also used in the Seagate ST-251 MFM hard disk. 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 tri-state 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 by

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 (computing), processor instructions. It can be used to configure a system differently at diffe ...

, 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 to the processor at address $01, to completely expose almost the full 64 KB of RAM 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 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), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base u ...

-capable 8502 variant is used in the Commodore 128. All these CPUs are

opcode In computing, an opcode (abbreviated from operation code) is an enumerated value that specifies the operation to be performed. Opcodes are employed in hardware devices such as arithmetic logic units (ALUs), central processing units (CPUs), and ...

compatible (including undocumented opcodes).

MOS 6510T

The Commodore 1551 disk drive (for the

Commodore Plus/4 The Commodore Plus/4 is a home computer released by Commodore International in 1984. It was part of the Commodore 264 series, which also included the Commodore 16 and Commodore 116 models. The Plus/4 was marketed as "the productivity computer wit ...

) 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 (preliminary, Nov. 1982, PDF format)
*
komkon.org - Computer Emulation Resources
(includes downloadable source code for 6502) * {{DEFAULTSORT:Mos Technology 6510 65xx microprocessors MOS Technology microprocessors Commodore 64 8-bit microprocessors

Use