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What makes a ROM a programmable logic device?
The information is embedded in the ROM, in the form of bits, by a process known as programming the ROM . Here, programming is used to refer to the hardware procedure which specifies the bits that are going to be inserted in the hardware configuration of the device . And this is what makes ROM a Programmable Logic Device (PLD) .
What is the internal structure of a ROM?
ROM (read-only memory) structure. Circuit Description. This applet demonstrates the internal structure of a read-only memory or ROM. A rather small memory size of 16 words of 8 bits each is used. From left to right, the circuit consists of three stages. The first stage, usually called address-decoder in memory circuits, is a standard demultiplexer.
How are memory blocks organized in a ROM?
Each memory block uses approximately the same number of wordlines and bitlines (the applet has 16 wordlines and 8 bitlines). For example, a good size for one memory block might consist of 256 wordlines and 256 bitlines. This means that a 64Kx8 bit ROM would be organized internally as a set of (65536×8) / (256×256) = 8 memory blocks.
How is the classification of ROM mask ROM done?
Classification Of ROM Mask ROM – In this type of ROM, the specification of the ROM (its contents and their location), is taken by the manufacturer from the customer in tabular form in a specified format and then makes corresponding masks for the paths to produce the desired output.
How is the PLA a programmable logic device?
The PLA in Figure 7.2.2 has been programmed to provide the three functions: Read only memory can be implemented as a programmable logic device where only the OR plane can be programmed. The AND gate plane is wired to provide all the minterms. Thus, the inputs to the ROM can be thought of as addresses.
What are the different types of programmable logic devices?
Next Page Programmable Logic Devices P L D s are the integrated circuits. They contain an array of AND gates & another array of OR gates. There are three kinds of PLDs based on the type of array s, which has programmable feature.
What does programming mean in programmable logic array?
Programmable Logic Array The process of entering the information into these devices is known as programming. Basically, users can program these devices or ICs electrically in order to implement the Boolean functions based on the requirement. Here, the term programming refers to hardware programming but not software programming.