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ADDRESSING MODES
S3C9454B/F9454B
3-10
DIRECT ADDRESS MODE (DA)
In Direct Address (DA) mode, the instruction provides the operand's 16-bit memory address. Jump (JP) and Call
(CALL) instructions use this addressing mode to specify the 16-bit destination address that is loaded into the PC
whenever a JP or CALL instruction is executed.
The LDC and LDE instructions can use Direct Address mode to specify the source or destination address for Load
operations to program memory (LDC) or to external data memory (LDE), if implemented.
Sample Instructions:
LDC
R5,1234H ; The values in the program address (1234H)are loaded
into register R5.
LDE
R5,1234H ; Identical operation to LDC example, except that
external program memory is accessed.
dst/src
OPCODE
Program Memory
"0" or "1"
Lower Address Byte
LSB Selects Program
Memory or Data Memory:
"0" = Program Memory
"1" = Data Memory
Memory
Address
Used
Upper Address Byte
Program or
Data Memory
Figure 3-10. Direct Addressing for Load Instructions
Summary of Contents for S3C9454B
Page 1: ...S3C9454B F9454B 8 BIT CMOS MICROCONTROLLER USER S MANUAL Revision 1 ...
Page 25: ...PRODUCT OVERVIEW S3C9454B F9454B 1 10 NOTES ...
Page 35: ...ADDRESS SPACES S3C9454B F9454B 2 10 NOTES ...
Page 65: ...CONTROL REGISTERS S3C9454B F9454B 4 18 NOTES ...
Page 123: ...CLOCK CIRCUIT S3C9454B F9454B 7 4 NOTES ...
Page 133: ...RESET and POWER DOWN S39454B F9454B 8 10 NOTES ...
Page 145: ...I O PORTS S3C9454B F9454B 9 12 NOTES ...
Page 173: ...A D CONVERTER S3C9454B F9454B 12 8 NOTES ...
Page 183: ...ELECTRICAL DATA S3C9454B F9454B 13 10 NOTES ...