CHAPTER 3 CPU ARCHITECTURE
Preliminary User’s Manual U16315EJ1V0UD
52
3.1.1 Internal program memory space
The internal program memory space stores the program and table data. Normally, it is addressed with the program
counter (PC).
78K0/KD1 Series products incorporate internal ROM (or flash memory), as shown below.
Table 3-2. Internal Memory Capacity
Internal ROM
Part Number
Structure
Capacity
µ
PD780121
8192
×
8 bits (0000H to 1FFFH)
µ
PD780122
16384
×
8 bits (0000H to 3FFFH)
µ
PD780123
24576
×
8 bits (0000H to 5FFFH)
µ
PD780124
Mask ROM
µ
PD78F0124
Flash memory
32768
×
8 bits (0000H to 7FFFH)
The internal program memory space is divided into the following areas.
(1) Vector table area
The 64-byte area 0000H to 003FH is reserved as a vector table area. The program start addresses for branch
upon RESET input or generation of each interrupt request are stored in the vector table area.
Of the 16-bit address, the lower 8 bits are stored at even addresses and the higher 8 bits are stored at odd
addresses.
Table 3-3. Vector Table
Vector Table Address
Interrupt Source
Vector Table Address
Interrupt Source
001AH
INTTMH1
0000H
RESET input, POC, LVI,
clock monitor, WDT
001CH
INTTMH0
0004H
INTLVI
001EH
INTTM50
0006H
INTP0
0020H
INTTM000
0008H
INTP1
0022H
INTTM010
000AH
INTP2
0024H
INTAD
000CH
INTP3
0026H
INTSR0
000EH
INTP4
0028H
INTWTI
0010H
INTP5
002AH
INTTM51
0012H
INTSRE6
002CH
INTKR
0014H
INTSR6
002EH
INTWT
0016H
INTST6
0030H
INTP6
0018H
INTCSI10/INTST0
(2) CALLT instruction table area
The 64-byte area 0040H to 007FH can store the subroutine entry address of a 1-byte call instruction (CALLT).
(3) CALLF instruction entry area
The area 0800H to 0FFFH can perform a direct subroutine call with a 2-byte call instruction (CALLF).