CHAPTER 3 CPU ARCHITECTURE
User’s Manual U16898EJ3V0UD
29
3.1.1 Internal program memory space
The internal program memory space stores programs and table data. This space is usually addressed by the
program counter (PC).
The 78K0S/KA1+ provides the following internal ROMs (or flash memory) containing the following capacities.
Table 3-1. Internal ROM Capacity
Internal ROM
Part Number
Structure Capacity
µ
PD78F9221 2,048
×
8 bits
µ
PD78F9222
Flash memory
4,096
×
8 bits
The following areas are allocated to the internal program memory space.
(1) Vector table area
The 34-byte area of addresses 0000H to 0021H is reserved as a vector table area. This area stores program
start addresses to be used when branching by Reset or interrupt request generation. Of a
16-bit address, the lower 8 bits are stored in an even address, and the higher 8 bits are stored in an odd
address.
Table 3-2. Vector Table
Vector Table Address
Interrupt Request
Vector Table Address
Interrupt Request
0000H Reset 0012H INTAD
0006H INTLVI 0016H INTP2
0008H INTP0 0018H INTP3
000AH INP1 001AH INTTM80
000CH INTTMH1
001CH INTSRE6
000EH INTTM000
001EH INTSR6
0010H INTTM010
0020H INTST6
Caution No interrupt sources correspond to the vector table address 0014H.
(2) CALLT instruction table area
The subroutine entry address of a 1-byte call instruction (CALLT) can be stored in the 64-byte area of
addresses 0040H to 007FH.
(3) Option byte area
The option byte area is the 1-byte area of address 0080H. For details, refer to
CHAPTER 17 OPTION BYTE
.
(4) Protect byte area
The protect byte area is the 1-byte area of address 0081H. For details, refer to
CHAPTER 18 FLASH
MEMORY
.
3.1.2 Internal data memory space
128-byte internal high-speed RAM is provided in the
µ
PD78F9221 and 256-byte in the
µ
PD78F9222.
The internal high-speed RAM can also be used as a stack memory.