Hey guys, I am revising on the 8051 Microcontroller.

I face one problem here for this question especially question (c).

It stated CLR 78H. Does that means that the content of 78H will be cleared and become 00H ?

Thanks !

 

http://www.win.tue.nl/~aeb/comp/8051/set8051.html#51clr

It clears bit #78h in the bit-addressable segment (in RAM 20h-2Fh) not register 78h. If I read it right, bit 78h is the LSbit of RAM register 2Fh.

CLR A clears all bits of the accumulator, CLR C clears the carry, CLR (anything else) clears one of the RAM bits. To clear other registers you'd use MOV Rn,#00h

 

Its a poor question.
Clearing something to 00h suggests clearing 8 bits.
Clearing a bit to 0b is something different.

 

Hi... just curious... may I know what institution is this? Questions are asked in 2 languages?

 

Hi... just curious... may I know what institution is this? Questions are asked in 2 languages?

It is in Malaysia. Some institutions do use two languages in the question papers.