GMS81508A Datasheet, PDF (17/91 Pages) Hynix Semiconductor – USERS MANUAL

HYUNDAI MicroElectronics
2.2. MEMORY SPACE
All RAM ,ROM,I/O, Peripheral Register are placed in the same memory area. Therefore, same
instructions enable both data transfer and operation without the need to distinguish memory and
I/O. The program counter of GMS81508/16 consists of 16-bit and memory addressing space is 64K
byte.
2.2.1. RAM area

RAM(includes stack area) is 448 Bytes ( 0000_H 01FF_H ).
The internal RAM is used for data storage, subroutine calling or stack area when interrupts occur.
When RAM is used as the stack area, the depth of the subroutine "nesting" and the interrupt levels
should be kept in mind in order to avoid destruction of the RAM contents.
2.2.2. Peripheral Register area

Address 00C0_H 00FF_H are assigned for peripheral register.
2.2.3. Program ROM area

PCALL subroutines must be located in PCALL area ( FF00_H FFBF_H ).

TCALL vector area ( FFC0_H FFDF_H ) has the vector address corresponding to TCALL
instruction.

Interrupt Vector area ( FFE0_H FFFF_H ) has the vector address of interrupts, inclusive RESET.
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