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Semiconductor Group
25
Memory Organization
The following paragraphs give a general overview of the special function register and refer to
sections where a more detailed description can be found.
Accumulator, SFR Address 0E0H
ACC is the symbol for the accumulator register. The mnemonics for accumulator-specific
instructions, however, refer to the accumulator simply as A.
Figure 4-4
Program Status Word Register (PSW), SFR Address 0D0H
The PSW register contains program status information.
B Register, SPF Address 0F0H
The B register is used during multiply and divide and serves as both source and destination. For
other instructions it can be treated as another scratch pad register.
Stack Pointer, SFR Address 081H
The Stack Pointer (SP) register is 8 bits wide. It is incriminated before data is stored during PUSH
and CALL executions and decremented after data is popped during a POP and RET (RETI)
execution, i.e. it always points to the last valid stack byte. While the stack may reside anywhere in
on-chip RAM, the stack pointer is initialized to 07H after a reset. This causes the stack to begin at
location 08H above register bank zero. The SP can be read or written under software control.
Bit
Function
CY
Carry flag
AC
Auxiliary carry flag (for BCD operations)
F0
General purpose user flag 0
RS1
RS0
0
0
0
1
1
0
1
1
Register bank select control bits
Bank 0 selected, data address 00H - 07H
Bank 1 selected, data address 08H - 0FH
Bank 2 selected, data address 10H - 17H
Bank 3 selected, data address 18H - 1F7
OV
Overflow flag
F1
General purpose user flag
P
Parity flag. Set/cleared by hardware each instruction cycle to indicate an odd/
even number of "one" bits in the accumulator, i.e. even parity.
0D7H 0D6H 0D5H 0D4H 0D3H 0D2H 0D1H 0D0H
CY
AC
F0
RS1
RS0
OV
F1
P
0D0H
PSW
*
Summary of Contents for SAB 80515 Series
Page 9: ...Semiconductor Group 9 Introduction Figure 1 2 Block Diagram ...
Page 12: ...Semiconductor Group 12 Fundamental Structure Figure 2 1 Detailed Block Diagram ...
Page 18: ...Semiconductor Group 18 Central Processing Unit Figure 3 1 Fetch Execute Sequence ...
Page 73: ...Semiconductor Group 73 On Chip Peripheral Components Figure 7 25 A D Converter Block Diagram ...
Page 83: ...Semiconductor Group 83 On Chip Peripheral Components Figure 7 33 a Timer 2 Block Diagram ...
Page 215: ...Device Specifications Semiconductor Group 215 ...
Page 217: ...Device Specifications Semiconductor Group 217 Pin Configuration P LCC 68 ...
Page 219: ...Device Specifications Semiconductor Group 219 Logic Symbol ...
Page 226: ...Device Specifications Semiconductor Group 226 Figure 1 Block Diagram ...
Page 229: ...Device Specifications Semiconductor Group 229 Figure 2 Memory Address Spaces ...
Page 239: ...Device Specifications Semiconductor Group 239 Figure 4 Block Diagram of the A D Converter ...
Page 241: ...Device Specifications Semiconductor Group 241 Figure 5 Interrupt Request Sources ...
Page 242: ...Device Specifications Semiconductor Group 242 Figure 6 Interrupt Priority Level Structure ...