25c3: The Ultimate Commodore 64 Talk
Christiaan008・2 minutes read
The text delves into the history and technical details of the Commodore 64, discussing its superior chip design, key features, and impressive graphics capabilities, such as the 6502 CPU with various addressing modes and the VIC video chip supporting sprites and different graphics modes. It highlights tricks and effects like interlacing for additional colors, border area expansion for visual space, and VSP for screen shifting, showcasing the advanced capabilities and creativity possible on the Commodore 64.
Insights
- The Commodore 64, with its impressive chip design and 64KB memory, outsold its successors and featured various models, showcasing advanced graphics capabilities through demos and games.
- The 6502 CPU in the Commodore 64, with unique assembly language and addressing modes, required cycle counting for memory access, had specific instructions with varying cycle counts, and needed workarounds for chip bugs, leading to innovative programming techniques like passing data to subroutines and self-modification.
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Recent questions
What is the history of the Commodore 64?
The Commodore 64 was released in 1982 by Commodore, founded by Jack Tramiel in 1954. It featured superior chip design and graphics capabilities, outselling its successors with 17 million units sold between 1982 and 1994. The company initially produced calculators, later acquiring MOS Technology and expanding into home computers with models like the Commodore PET, VIC-20, and the successful Commodore 64 with 64KB of memory.
What are the key features of the Commodore 64?
The Commodore 64 featured various models, including an original version, a flat design, a limited golden edition, and a portable version. Externally, it had two control ports, expansion ports, RF and S-video connectors, a serial bus, tape connector, and a user port. Internally, it housed the 6510 CPU, two CIA controllers, the SID sound chip, and the VIC video chip, each serving specific functions. The system booted directly into BASIC from ROM, showcasing impressive graphics capabilities through demos and games.
How does the 6502 CPU function in the Commodore 64?
The 6502 CPU, designed in 1975, featured a unique assembly language with various addressing modes for efficient programming. The talk delves into the 6502's instruction set, addressing modes like immediate, absolute, zero page, and register addressing, along with control flow instructions and interrupt handling mechanisms. The CPU requires cycle counting for memory access, with each access taking one cycle and no instruction less than two cycles.
What are the capabilities of the SID sound chip in the Commodore 64?
The SID 6581 sound chip in the Commodore 64 has three independent voices with analog and digital control. Each voice can produce various waveforms like sawtooth, triangle, pulse, or noise, with volume controlled by an envelope. The SID also features analog filters for effects, offering low pass, high pass, or band pass options, along with ring modulators and oscillator sync.
How does the VIC chip contribute to the graphics of the Commodore 64?
The VIC 6569 chip in the Commodore 64 supports a 40x25 screen or a 320x200 Graphics mode, with 16 built-in colors and the ability to address 16 kilobytes of RAM. It can display 256 different characters with 16 colors each, using an 8x8 pixel character set encoded in character ROM. The VIC offers various modes like enhanced background, multicolor, and bitmap mode, allowing for different color combinations and effects.
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