Internal Program Memory Space; Internal Data Memory Space - NEC PD789860 User Manual

4.1.1 Internal program memory space

The internal program memory space stores programs and table data. This space is usually addressed by the
program counter (PC).
µ
The PD789860, 789861 Subseries provide the following internal ROMs (or EEPROM) containing the following
capacities.
Part Number
µ
PD789860, 789861
µ
PD78E9860A, 78E9861A
The following areas are allocated to the internal program memory space:
(1) Vector table area
The 14-byte area of addresses 0000H to 000DH is reserved as a vector table area. This area stores
program start addresses to be used when branching by RESET input 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.
Vector Table Address
0000H
0002H
0004H
0006H
(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.

4.1.2 Internal data memory space

µ
The PD789860, 789861 Subseries provide the following RAMs.
(1) Internal high-speed RAM
The internal high-speed RAM is provided in the area of FE80H to FEFFH.
The internal high-speed RAM can also be used as a stack memory.
(2) EEPROM
The EEPROM is provided in the area of F800H to F81FH.
For details of EEPROM, see CHAPTER 5 EEPROM (DATA MEMORY).
CHAPTER 4 CPU ARCHITECTURE
Table 4-1. Internal ROM Capacity
Table 4-2. Vector Table
Interrupt Request
RESET input
INTKR1
INTWDT
INTTM30
User's Manual U14826EJ5V0UD
Internal ROM
Structure
Mask ROM
EEPROM
Vector Table Address
0008H
000AH
000CH
Capacity
4,096 × 8 bits
Interrupt Request
INTTM40
INTLVI1
INTEE0
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