IBM EM78P312N manual Instruction Set, Bit Microcontroller

EM78P312N

8-Bit Microcontroller

5.19 Instruction Set

Each instruction in the instruction set is a 13-bit word divided into an OP code and one or more operands. Normally, all instructions are executed within one single instruction cycle (one instruction consists of 2 oscillator periods), unless the program counter is changed by instruction "MOV R2,A", "ADD R2,A", or by instructions of arithmetic or logic operation on R2 (e.g. "SUB R2,A", "BS(C) R2,6", "CLR R2", ⋅⋅⋅⋅). In this case, the execution takes two instruction cycles.

In case the instruction cycle specification is not suitable for certain applications, try to modify the instruction as follows:

(A)Change one instruction cycle to consist of 4 oscillator periods.

(B)The following commands are executed within two instruction cycles; "JMP", "CALL", "RET", "RETL", "RETI", including the conditional skip ("JBS", "JBC", "JZ", "JZA", "DJZ", "DJZA") instructions. In addition, instructions that are written to the program counter are executed within two instruction cycles.

Case (A) is selected by the CODE Option bit, called CLK. One instruction cycle consists of two oscillator clocks if CLK is low, and four oscillator clocks if CLK is high.

Note that once the 4 oscillator periods within one instruction cycle is selected as in Case (A), the internal clock source to TCC should be CLK=Fosc/4, not Fosc/2.

Furthermore, the instruction set has the following features:

(1)Every bit of any register can be set, cleared, or tested directly.

(2)The I/O register can be regarded as general register. That is, the same instruction can operate on I/O register.

Convention:

R = Register designator that specifies which one of the registers (including operation and general purpose registers) is to be utilized by the instruction.

b = Bit field designator that selects the value for the bit located in the register R and which affects the operation.

k = 8 or 10-bit constant or literal value

		Binary Instruction			Hex	Mnemonic		Operation	Status
									Affected
	0	0000	0000	0000	0000	NOP		No Operation	None
	0	0000	0000	0001	0001	DAA		Decimal Adjust A	C
	0	0000	0000	0010	0002	CONTW		A → CONT	None
	0	0000	0000	0011	0003	SLEP		0 → WDT, Stop	T, P
								oscillator
	0	0000	0000	0100	0004	WDTC		0 → WDT	T, P
	0	0000	0000	rrrr	000r	IOW	R	A → IOCR	None 1
	0	0000	0001	0000	0010	ENI		Enable Interrupt	None
	0	0000	0001	0001	0011	DISI		Disable Interrupt	None
	0	0000	0001	0010	0012	RET		[Top of Stack] → PC	None
	0	0000	0001	0011	0013	RETI		[Top of Stack] → PC,	None
								Enable Interrupt
	0	0000	0001	0100	0014	CONTR		CONT → A	None
	0	0000	0001	rrrr	001r	IOR	R	IOCR → A	None 1
56 •							Product Specification (V1.0) 10.03.2006

(This specification is subject to change without further notice)