Lesson plan
4-bit computing
4-bit computing is the use of computer architectures in which integers and other data units are 4 bits wide. 4-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data buses of that size. A group of four bits is also called a nibble and has 2 4 = 16 possible values, with a range of 0 to 15. 4-bit computation is largely obsolete, i.e. CPUs supporting 4-bit as the maximum size, or 4-bit data bus are no longer available, but 4-bit microcontrollers, such as the EM Microelectronic EM6580, are still available . 4-bit processors were widely used in electronic calculators and other roles where decimal math was used, like electronic cash registers, microwave oven timers, and so forth. This is because a 4-bit value holds a single binary-coded decimal (BCD) digit, making it a natural size for directly processing decimal values. As a 4-bit value is generally too small to hold a memory address for real-world programs or data, the address bus of these systems was generally larger. For instance, the canonical 4-bit microprocessor, the Intel 4004, had a 12-bit address format. 4-bit designs were used only for a short period when integrated circuits were still expensive, and were found primarily in cost-sensitive roles.…
Article summary
4-bit computing is the use of computer architectures in which integers and other data units are 4 bits wide. 4-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data buses of that size. A group of four bits is also called a nibble and has 2 4 = 16 possible values, with a range of 0 to 15. 4-bit computation is largely obsolete, i.e. CPUs supporting 4-bit as the maximum size, or 4-bit data bus are no longer available, but 4-bit microcontrollers, such as the EM Microelectronic EM6580, are still available . 4-bit processors were widely used in electronic calculators and other roles where decimal math was used, like electronic cash registers, microwave oven timers, and so forth. This is because a 4-bit value holds a single binary-coded decimal (BCD) digit, making it a natural size for directly processing decimal values. As a 4-bit value is generally too small to hold a memory address for real-world programs or data, the address bus of these systems was generally larger. For instance, the canonical 4-bit microprocessor, the Intel 4004, had a 12-bit address format. 4-bit designs were used only for a short period when integrated circuits were still expensive, and were found primarily in cost-sensitive roles.…
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.