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FIGURE 2.2: Loading of PC in Different Situations
Situation 1: GOTO Instruction
PCH
PCL
10 9
8
7
0
PC
-
-
-
-
-
PCHBUF
Situation 2: CALL Instruction
PCH
PCL
10 9
8
7
0
PC
-
-
-
-
-
PCHBUF
Situation 3: RETIA, RETFIE, or RETURN Instruction
PCH
PCL
10 9
8
7
0
PC
-
-
-
-
-
PCHBUF
Situation 4: Instruction with PCL as destination
PCH
PCL
10 9
8
7
0
PC
-
-
-
-
-
PCHBUF
Note: 1. Bits PC<10:9> and PCHBUF<2:1> are unimplemented for TLC154/155.
Bits PC<10> and PCHBUF<2> are unimplemented for TLC156.
2. PCHBUF is used only for instruction with PCL as destination for TLC154/155/156.
PCHBUF is used for instruction with PCL as destination, GOTO and CALL instructions for TLC157.
Opcode<9:0>
PCHBUF<2:0>
ALU result<7:0>
or Opcode<7:0>
STACK<10:0>
STACK<10:0>
PCHBUF<2>
Opcode<9:0>
PCHBUF<2>
TLC
TLC156
Rev0.95 Nov 20, 2003
P.2/TLC156