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The ATTINY24V instruction set is highly orthogonal and is comprised of three basic categories.
· Byte-oriented operations
· Bit-oriented operations
· Literal and control operations
Each PIC16 instruction is a 12-bit word divided into an opcode, which specifies the instruction type and one or more operands which further specify the operation of the instruction.
The formats for each of the categories is presented in Figure 10-1, while the various opcode fields are summarized in Table 10-1 before Break Protected AVR Chip ATTINY24V Firmware.
For byte-oriented instructions, ‘f’ represents a file register designator and ‘d’ represents a destination designator. The file register designator specifies which file register is to be used by the instruction.
The destination designator specifies where the result of the operation is to be placed. If ‘d’ is ‘0’, the result is placed in the W register. If ‘d’ is ‘1’, the result is placed in the file register specified in the instruction.
For bit-oriented instructions, ‘b’ represents a bit field designator which selects the number of the bit affected by the operation, while ‘f’ represents the number of the file in which the bit is located if Break Protected AVR Chip ATTINY24V Firmware.
For literal and control operations, ‘k’ represents an 8 or 9-bit constant or literal value.
All instructions are executed within a single instruction cycle, unless a conditional test is true or the firmware counter is changed as a result of an instruction. In this case, the execution takes two instruction cycles.
One instruction cycle consists of four oscillator periods. Thus, for an oscillator frequency of 4 MHz, the normal instruction execution time is 1 ìs. If a conditional test is true or the firmware counter is changed as a result of an instruction, the instruction execution time is 2 ìs when Break Protected AVR Chip ATTINY24V Firmware.
Figure 10-1 shows the three general formats that the instructions can have. All examples in the figure use the following format to represent a hexadecimal number: 0xhhh where ‘h’ signifies a hexadecimal digit after Break IC.