PIC MICROCONTROLLER
ARCHITECTURE OF 8085
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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bank 0
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bank 1
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bank 2
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bank 3
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Detailed explanation-1: -With the help of three left bits (IRP, RP1, and RP0) one can control the transition between the banks: IRP-Register Bank Select bit, used for indirect addressing method. RP1:RP0:-Register Bank Select bits, used for direct addressing method.
Detailed explanation-2: -Selecting one of the banks is done via RP0 bit in STATUS register. Instruction BCF clears bit RP0 (RP0=0) in STATUS register and thus sets up bank 0. Instruction BSF sets the bit RP0 (RP0=1) in STATUS register and thus sets up bank1. It is useful to consider what would happen if the wrong bank was selected.
Detailed explanation-3: -Bits RP1 and RP0 (Register Page 1 and Register Page 0 respectively) serve as the upper 2 address bits for instructions which directly address the iRAM locations. This makes bit RP1 a 0 while making bit RP0 a 1, which gives us the leading “01” in TRISA’s address.
Detailed explanation-4: -The PIC16F877 chip only has four banks (BANK 0, BANK 1, BANK 2, and BANK4). Each bank holds 128 bytes of addressable memory.