GMS81508B HYNIX [Hynix Semiconductor], GMS81508B Datasheet - Page 24

• Manufacturer Part Number: GMS81508B
• Description: HYUNDAI MICRO ELECTRONICS 8-BIT SINGLE-CHIP MICROCONTROLLERS
• Manufacturer: HYNIX [Hynix Semiconductor]

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 FFFF
Figure 8-5, shows a map of Program Memory. After reset,
the CPU begins execution from reset vector which is stored
in address FFFE
As shown in Figure 8-5, each area is assigned a fixed loca-
tion in Program Memory. Program Memory area contains
the user program.
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,
DEC. 1999 Ver 1.04
C000
E000
FEFF
FF00
FFC0
FFDF
FFE0
FFFF
A000
Figure 8-5 Program Memory Map
H
H
H
H
H
H
H
H
H
H
will cause a wrap-around to 0000
H
TCALL area
Vector Area
Interrupt
and FFFF
H
as shown in Figure 8-6.
H
.
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
TCALL14, etc., as shown in Figure 8-7.
Example: Usage of TCALL
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
interval: 0FFF8
0FFFA
Any area from 0FF00
used, its service location is available as general purpose
Program Memory.
H
and 0FFFB
Address
0FFE0H
H
Figure 8-6 Interrupt Vector Area
. The interrupt service locations spaces 2-byte
E2
E4
E6
E8
EA
EC
EE
F0
F2
F4
F6
F8
FA
FC
FE
H
NOTE:
“-” means reserved area.
and 0FFF9
H
H
for External Interrupt 0, etc.
Serial Communication Interface
to 0FFFF
Watchdog Timer Interrupt
Timer/Counter 2 Interrupt
Timer/Counter 0 Interrupt
Timer/Counter 3 Interrupt
Timer/Counter 1 Interrupt
Vector Area Memory
Basic Interval Timer
RESET Vector Area
External Interrupt 2
External Interrupt 3
External Interrupt 1
External Interrupt 0
H
A/D Converter
for TCALL15, 0FFC2
H
GMS81508B/16B/24B
-
-
-
-
-
-
for External Interrupt 1,
H
, if it is not going to be
H
21
for