Microprocessors

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Microprocessors

• Single-bit Instructions Ch8

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Addressable Bits
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General Single-bit Instruction Set

• SETB bit forces a 1
• CLR bit forces a 0
• CPL bit forces a change
• JB bit,destination checks bit and jumps on 1
• JNB bit, destination checks bit and jumps on 0
• JBC bit, destination checks bit, forces a 0 and
  jumps on 1.

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CY Single-bit Instruction Set

• MOV bit, C copies CY into addressed bit
• MOV C, bit copies bit addressed bit into CY
• JNC destination jumps if CY 0
• JC destination jumps if CY 1
• ANL C, bit CY CY ANDed to addressed bit
• ANL C, /bit CY CY ANDed to comp bit
• ORL C, bit CY CY ORed to addressed bit
• ORL C, /bit CY CY ORed to comp bit

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A VERY BIG DEALTo use these instructions, you
must first configure the pins for input!

• MOV A, PX Reads all 8 port pins.
• MOV C, PX.Y Reads a single port pin.
• JNB PX.Y, dest Tests a single port pin.
• JB PX.Y, dest Tests a single port pin.

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These instructions read a port not configured for
input.

• ANL Px
• ORL Px
• XRL Px
• JBC Px.y, dest
• CPL Px.y

• INC Px
• DEC Px
• DJNZ Px.y, dest
• MOV Px.y
• CLR Px.y
• SETB Px.y