HT48CXX データシートの表示（PDF） - Holtek Semiconductor

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HT48CXX

8-Bit Microcontroller Series

Holtek Semiconductor 

HT48CXX/HT48RXX

Program memory – ROM

The program memory (ROM) is used to store the

program instructions that are to be executed. It

contains data, table, and interrupt entries, and

is organized into 1024×14 bits, 2048×14 bits,

4096×15 bits, or 8192×16 bits according to the mi-

crocontroller (HT48C10/ HT48C30/HT48C50/

HT48C70) selected. These bits are all addressed by the

PC and table pointer.

Certain locations in the ROM stated below are

reserved for special usage in the four microcon-

trollers except location 00CH which is used for

the HT48C50/HT48C70 exclusively.

• Location 000H

Location 000H is reserved for program in-

itialization. After chip reset, the program al-

ways begins execution at this area.

• Location 004H

Location 004H is reserved for external inter-

rupt service program. If the INT input pin is

activated, the interrupt is enabled, and the

stack is not full, the program begins execution

at location 004H.

• Location 008H

Location 008H is reserved for the timer/event

counter interrupt service program of the

HT48C10/HT48C30 and for the timer/event

counter 0 interrupt service program of the

Program memory

HT48C50/HT48C70. If the timer interrupt re-

sults from a timer/event counter overflow of

the HT48C10/HT48C30 or a timer/event

counter 0 overflow of the HT48C50/HT48C70,

and the interrupt is enabled, and the stack is

not full, the program begins execution at loca-

tion 008H.

Mode

Initial reset

External interrupt

Timer/event counter 0 overflow

Timer/event counter 1 overflow

Skip

Loading PCL

Jump, call branch

Return from subroutine

Contents of Program Counter (m bits)

0000H

0004H

0008H

000CH

PC+2

Low byte replaced by instruction code

Instruction code

Stack register

Notes: m=10 for the HT48C10

m=11 for the HT48C30

m=12 for the HT48C50

m=13 for the HT48C70

14

25th May ’99

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