Chapter 1: A Look Back at the Commodore 64

Reflecting on my childhood, the Commodore 64 stands out as a pivotal part of my early experiences with technology. This article is a revised version of a piece I wrote for a now-closed blog, shedding light on this classic computer that still holds a place in my collection.

My first Commodore 64 was a vintage ‘Silver Label’ model. It was during the mid-1980s that I found myself increasingly dissatisfied with the limitations of my Sinclair ZX Spectrum. I was eager to explore sound and music, yet this was a significant shortcoming of the Spectrum. Transitioning from high school to college, I encountered fellow students who owned Commodore 64s. Intrigued by the capabilities of the 6581 SID chip—the sound generator in the C64—I was compelled to experience it for myself.

Goodbye, ZX Spectrum

My parents made it clear that I couldn’t keep both computers; my ZX Spectrum had to go. With a heavy heart, I bid farewell to the Spectrum and welcomed the Commodore 64 into my life. Given its higher price, we opted for a second-hand unit. The seller also offered a disk drive, but our budget didn't allow for that luxury, so I relied solely on the cassette system.

The C64’s keyboard was a notable improvement over the Spectrum’s, and I appreciated the dedicated cassette recorder. Unlike the Spectrum, which required adjusting volume levels on a standard audio cassette recorder, the C64 made the process much simpler. However, the cassette interface was significantly slower—about five times slower than that of the Spectrum. This inconvenience led to the popularization of ‘turbo loader’ software to mitigate the issue.

Playing with the SID Chip

Once I had my Commodore 64 set up, I eagerly perused the manuals to learn how to create sounds. I hoped for an experience akin to using the BBC Micro at school, complete with commands like SOUND and ENVELOPE. Unfortunately, I quickly realized that the C64’s BASIC language had its shortcomings.

No BASIC Sound Commands

The built-in BASIC didn’t offer any sound commands, requiring users to control the SID chip using POKE commands directly. This was disappointing; even the budget-friendly Spectrum had a BEEP command for sound. Despite the initial frustration, I persisted and eventually managed to produce some sounds on my first day with the device.

Mini Synthesizer

The SID chip resembled a mini synthesizer, equipped with three oscillators capable of generating triangle, sawtooth, pulse, or noise waveforms. Each oscillator featured an ADSR envelope generator (attack, decay, sustain, release) and a filter with various modes, along with support for ring modulation, allowing for bell-like sounds.

Creating Sounds and Music

With further reading and numerous POKE commands, I was astounded by the audio capabilities of the SID chip. There were minor quirks, like a ‘click’ sound when adjusting the master volume, but the potential was impressive. I wrote my own BASIC programs to have the 64 play tunes and even ventured into 6502 machine code for specific tasks. A college classmate introduced me to software called Synth Sound, which played a range of popular songs and sounded fantastic when connected to a hi-fi system. Later, a colleague gifted me Music Studio, marking my first experience with music software. While it was remarkable for its time, editing notes with a joystick proved to be a slow and frustrating process.

Graphics Capabilities

The Commodore 64 was renowned for its graphical features, particularly sprite graphics and hardware support for smooth scrolling. However, BASIC lacked adequate support for graphics, necessitating the use of numerous POKE commands to manipulate the hardware, which could be daunting for newcomers. Upon startup, the default mode displayed 40 x 25 text, while high-resolution graphics modes offered 320 x 200 with two colors or 160 x 200 with four colors per 8 x 8 block. The color palette provided 16 choices, and the system supported eight hardware sprites with their own color registers. Through ‘raster interrupt’ programming, additional colors and sprites could be implemented by adjusting graphics hardware registers at precise moments.

6510/6502 Architecture

Having previously programmed the Z80 processor of the Spectrum in assembly language, I was eager to see how the C64’s architecture differed. After studying the programmer’s reference guide for the C64’s 6510 processor, which was a variant of the 6502 used in machines like the BBC Micro and Apple II, I found that adapting took time due to the differences between the 6510 and Z80. Nevertheless, I soon got some simple programs operational. Learning about the 6510/6502 would later prove beneficial in my first job, where I worked with the Apple II.

The Commodore 64’s 6510 operated at around 1 MHz, which, surprisingly, compared favorably to the ZX Spectrum’s 3.5 MHz Z80. Although the 64 boasted 64 KB of RAM, not all of it was readily available for BASIC programs. By switching out components like the BASIC ROM, I could access the full RAM using assembly language.

Hardware Experiments

After experiencing issues with my ZX Spectrum’s aging card edge connector, I was pleased to find that the C64’s user port had a more forgiving pitch. The C64’s user port connected to a 6526 CIA chip (Complex Interface Adapter), simplifying the design for external hardware attachments. I attached both analog-to-digital and digital-to-analog converters, crafting assembly language code to control them. My goal was to record and play sound, transforming my C64 into a basic digital storage oscilloscope. However, the modest processor speed limited the sample rate, and it wasn’t until I upgraded to the Amiga 500 that I achieved better results.

Games and Popularity

Thanks to its sound, graphics, and built-in joystick ports, the Commodore 64 attracted a vast array of games, contributing to its popularity. Although I didn’t exclusively use my C64 for gaming, I amassed nearly thirty titles, spending considerable time immersed in them. Radar Rat Race was the only cartridge game I owned; it was enjoyable and loaded instantly.

The majority of my games were cassette-based, leading to longer loading times—sometimes exceeding 15 minutes! Fortunately, many later games featured fast loaders, significantly reducing load times to just a few minutes, bringing them in line with computers like the ZX Spectrum. I fondly recall playing Falcon Patrol, Flight Path 737, Dr Soft’s 747, ACE, Action Biker, Colony, and The Last V8, among others.

Commodore Bus

Regrettably, I never utilized a floppy disk drive with my Commodore 64, though I was aware that they connected via a serial bus, which also accommodated other peripherals such as printers. While the floppy drive was typically slow, fast loader software often improved transfer rates. I once contemplated designing a circuit to enable SD card storage, despite knowing that such solutions already existed. Ultimately, I opted for a ready-made option, though part of me regrets not attempting to create my own.

Other Commodore 8-Bit Machines

Though the Commodore 64 debuted in 1982, it was not the company’s first computer. The PET was released in 1977 as an expensive all-in-one machine, followed by the more affordable VIC-20 in 1981. After the C64, Commodore introduced the Commodore 16 and Plus/4 in 1984, and the Commodore 128 in 1985, which offered compatibility with the 64 but included additional features. However, none of these other models achieved the same level of success or appeal as the C64, which seemed to strike the perfect balance of features and price.

Conclusion

The Commodore 64 was instrumental in helping me acquire valuable skills, including 6502 assembly language programming, while igniting my passion for music synthesis. I still remember several 6502/6510 opcodes and various SID chip register addresses! I continue to own the Commodore 64 my parents gifted me in the mid-1980s, and it remains in perfect working order. Few of my other vintage computers have stood the test of time quite as well, likely because the C64 saw less use after I transitioned to an Amiga 500 in 1987. Nowadays, I lack the space to set up my vintage machines, but I enjoy the occasional game of Radar Rat Race or Action Biker. While I prefer using authentic hardware, emulators are more convenient for quick play sessions.

Do you have fond memories of the Commodore 64? Feel free to share your thoughts in the comments below.

If you appreciated this narrative, you may also enjoy other stories in this series:

Vintage Computers

Microcomputers from the 70s and 80s that shaped my experiences.

External Links

Commodore 64 (Wikipedia)

Commodore PET (Wikipedia)

Commodore VIC-20 (Wikipedia)

Commodore 16 (Wikipedia)

Commodore Plus/4 (Wikipedia)

Commodore 128 (Wikipedia)

Commodore Serial Bus (Wikipedia)

The first video, Commodore History Part 3 - The Commodore 64 (complete), provides an in-depth look at the history and legacy of the beloved C64. It's a must-watch for fans of retro technology!

The second video, The 8-bit home computer from 1975 you've never heard of, explores the lesser-known origins of home computing, adding context to the era of the Commodore 64.