What is the size of internal data memory in an 8051 microcontroller?

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ALP CBT 2 Electronic Mechanic Previous Paper: Held on 21 Jan 2019 Shift 2
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  1. 2048 bytes
  2. 1024 bytes
  3. 256 bytes
  4. 128 bytes

Answer (Detailed Solution Below)

Option 4 : 128 bytes
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Detailed Solution

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  • 8051 is an 8-bit microcontroller built with 40 pins DIP (dual inline package).
  • 8051 has internal RAM (128 Bytes) and ROM (4K Bytes).
  • Of the 128-byte internal RAM, only 16 bytes are bit-addressable. The rest must be accessed in byte format.

Notes:

The Block Diagram of an 8051 microcontroller is as shown:

F1 S.B Madhu 20.02.20 D2

In an 8051 microcontroller,

  • Internal RAM (data memory) - 128 bytes
  • Internal memory (code memory) - 4 kB (ROM)
  • Timer/counter - 2
  • No. of interrupt - 5
  • I/O pins - 32
  • Serial port - 1
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