em78p811 ELAN Microelectronics Corp, em78p811 Datasheet - Page 10

• Manufacturer Part Number: em78p811
• Description: 8-bit Micro-controller
• Manufacturer: ELAN Microelectronics Corp

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* This specification is subject to be changed without notice.
VII.1 Operational Registers
1. R0 (Indirect Addressing Register)
2. R1 (TCC)
3. R2 (Program Counter)
* R0 is not a physically implemented register. It is useful as indirect addressing pointer. Any instruction using R0 as
* Increased by an external signal edge applied to TCC , or by the instruction cycle clock.
Written and read by the program as any other register.
cleared to "0''.
cleared to "0''.
* "TBL" allows a relative address be added to the current PC, and contents of the ninth and tenth bits don't change.
The most significant bit (A10~A13) will be loaded with the content of bit PS0~PS3 in the status register (R5) upon
the execution of a "JMP'', "CALL'', "ADD R2,A'', or "MOV R2,A'' instruction.
register actually accesses data pointed by the RAM Select Register (R4).
* The structure is depicted in Fig. 4.
* Generates 16K × 13 on-chip ROM addresses to the relative programming instruction codes.
* "JMP" instruction allows the direct loading of the low 10 program counter bits.
* "CALL" instruction loads the low 10 bits of the PC, PC+1, and then push into the stack.
* "RET'' ("RETL k", "RETI") instruction loads the program counter with the contents at the top of stack.
* "MOV R2,A" allows the loading of an address from the A register to the PC, and the ninth and tenth bits are
* "ADD R2,A" allows a relative address be added to the current PC, and contents of the ninth and tenth bits are
1000
1001
1010
1011
1100
1101
1110
1111
PC
(ps3,ps2,ps1,ps0)
A13 A12 A11 A10
2000
23FF
2400
27FF
2800
2CFF
2D00
2FFF
3000
33FF
3400
37FF
3800
3CFF
3D00
3FFF
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Fig.4 Program counter organization
A9 A8
0000
0001
0010
0011
0100
0101
0110
0111
1D00
1FFF
A7
1000
13FF
1400
17FF
1800
1CFF
0000
03FF
0400
07FF
0800
0CFF
0D00
0FFF
9
A0
Page 0
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Page4
Page5
Page6
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CALL
RET
RETL
RETI
STACK1
STACK2
STACK3
STACK4
STACK5
STACK6
STACK7
STACK8
8-bit OTP Micro-controller
EM78P811