GMS81C5108 Datasheet, PDF (24/102 Pages) Hynix Semiconductor – HYNIX SEMICONDUCTOR INC. 8-BIT SINGLE-CHIP MICROCONTROLLERS

GMS81C5108
8.2 Program Memory
A 16-bit program counter is capable of addressing up to
64K bytes, but this device has 8K bytes program memory
space only physically implemented. Accessing a location
above FFFF_H will cause a wrap-around to 0000_H.
Figure 8-5 shows a map of Program Memory. After reset,
the CPU begins execution from reset vector which is stored
in address FFFE_H and FFFF_H as shown in Figure 8-6.
As shown in Figure 8-5, each area is assigned a fixed loca-
tion in Program Memory. Program Memory area contains
the user program.
E000_H
Example: Usage of TCALL
LDA
#5
TCALL 0FH
:
:
;
;TABLE CALL ROUTINE
;
FUNC_A: LDA LRG0
RET
;
FUNC_B: LDA LRG1 ₂
RET
;
;TABLE CALL ADD. AREA
;
ORG 0FFC0H
DW FUNC_A
DW FUNC_B
;1BYTE INSTRUCTION
;INSTEAD OF 2 BYTES
;NORMAL CALL
1
;TCALL ADDRESS AREA
FEFF_H
FF00_H
FFC0_H
FFDF_H
FFE0_H
FFFF_H
TCALL
AREA
INTERRUPT
VECTOR AREA
PROGRAM
MEMORY
PCALL
AREA
Figure 8-5 Program Memory Map
Page Call (PCALL) area contains subroutine program to
reduce program byte length by using 2 bytes PCALL in-
stead of 3 bytes CALL instruction. If it is frequently called,
it is more useful to save program byte length.
Table Call (TCALL) causes the CPU to jump to each
TCALL address, where it commences the execution of the
service routine. The Table Call service area spaces 2-byte
for every TCALL: 0FFC0_H for TCALL15, 0FFC2_H for
TCALL14, etc., as shown in Figure 8-7.
The interrupt causes the CPU to jump to specific location,
where it commences the execution of the service routine.
The External interrupt 0, for example, is assigned to loca-
tion 0FFFA_H. The interrupt service locations spaces 2-byte
interval: 0FFF8_H and 0FFF9_H for External Interrupt 1,
0FFFA_H and 0FFFB_H for External Interrupt 0, etc.
Any area from 0FF00_H to 0FFFF_H, if it is not going to be
used, its service location is available as general purpose
Program Memory.
Address
0FFE0_H
E2
E4
E6
E8
EA
EC
EE
F0
F2
F4
F6
F8
FA
FC
FE
Vector Area Memory
-
-
-
-
Watch Timer Interrupt Vector Area
Serial I/O Interrupt Vector Area
AD Converter Interrupt Vector Area
Remocon Interrupt Vector Area
External Interrupt 2 Vector Area
Timer/Counter 1 Interrupt Vector Area
Timer/Counter 0 Interrupt Vector Area
External Interrupt 1 Vector Area
External Interrupt 0 Vector Area
Basic Interval Timer Interrupt Vector Area
Key Scan Interrupt Vector Area
RESET Vector Area
NOTE:
“-” means reserved area.
Figure 8-6 Interrupt Vector Area
JUNE 2001 Ver 1.0
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