GMS82512/16/24
HYUNDAI MicroElectronics
8.2 Program Memory
A 16-bit program counter is capable of addressing up to
64K bytes, but this device has 24K bytes program memory
space only physically implemented. Accessing a location
above FFFFH will cause a wrap-around to 0000H.
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: 0FFC0H for TCALL15, 0FFC2H for
TCALL14, etc., as shown in Figure 8-7.
Figure 8-5, shows a map of Program Memory. After reset,
the CPU begins execution from reset vector which is stored
in address FFFEH and FFFFH as shown in Figure 8-6.
Example: Usage of TCALL
As shown in Figure 8-5, each area is assigned a fixed loca-
tion in Program Memory. Program Memory area contains
the user program.
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 0FFFAH. The interrupt service locations spaces 2-byte
interval: 0FFF8H and 0FFF9H for External Interrupt 1,
0FFFAH and 0FFFBH for External Interrupt 0, etc.
A000
C000
H
Any area from 0FF00H to 0FFFFH, if it is not going to be
used, its service location is available as general purpose
Program Memory.
H
Address
Vector Area Memory
0FFE0H
E2
-
D000
H
-
E4
-
E6
Basic Interval Timer
Watchdog Timer Interrupt
FEFF
E8
H
H
FF00
H
EA
A/D Co-nverter
EC
Timer/Counter 3 Interrupt
-
FFC0
EE
Timer/Counter 2 Interrupt
-
TCALL area
FFDF
H
H
F0
Timer/Counter 1 Interrupt
FFE0
Interrupt
Vector Area
F2
F4
F6
F8
FA
FC
FE
Timer/Counter 0 Interrupt
External Interrupt 3
FFFF
H
External Interrupt 2
External Interrupt 1
External Interrupt 0
-
RESET Vector Area
Figure 8-5 Program Memory Map
NOTE:
“-” means reserved area.
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,
Figure 8-6 Interrupt Vector Area
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FEB. 2000 Ver 1.00
HYNIX [ HYNIX SEMICONDUCTOR ]
