NEC PD75402A, PD75P402 user manual Program Memory ROM .... ,920 Words × 8 Bits, Program Memory Map

CHAPTER 4. INTERNAL CPU FUNCTIONS

4.2PROGRAM MEMORY (ROM) ..... 1,920 WORDS × 8 BITS

A mask programmable ROM of a 1,920-word × 8-bit configuration. It stores the program, table data, etc.

The program memory is addressed by the program counter. It is also possible to read the table data in the ROM by the table refer instruction (MOVT).

It is possible to branch to any area of the program memory by the branch instruction, subroutine call instruction (see Fig. 4-2). With the relative branch instruction (BR $addr), it is possible to branch to the range of (-15 to -1, +2 to +16) from the address indicated by the PC after the instruction execution.

The program memory’s addresses cover 000H to 77FH and the addresses shown below are assigned specially. All the areas excluding 000H and 001H are available as the normal program memory.

						Fig. 4-2 Program Memory Map
Address	7	6	5	4	3		0
0 0 0 H	0	0	0	0	0	Reset Start Address
						(high-order 3 bits)
0 0 1 H
		Reset Start Address (low-order 8 bits)
0 0 2 H	0	0	0	0	0	INTBT Start Address
						(high-order 3 bits)
0 0 3 H
		INTBT Start Address (low-order 8 bits)
0 0 4 H	0	0	0	0	0	INT0 Start Address
						(high-order 3 bits)
0 0 5 H		INT0 Start Address (low-order 8 bits)

0 0 8 H	0	0	0	0	0	INTCSI Start Address
						(high-order 3 bits)
0 0 9 H
		INTCSI Start Address (low-order 8 bits)

~	~
~	~

CALLF !faddr

Instruction Entry

Address

BRCB !caddr

Instruction Branch

Address

BR $addr

Instruction Relative

Branch Address

–15 to –1 +2 to +16

7 7 F H

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