UPD784224 Datasheet, PDF (20/92 Pages) NEC – 16/8-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784224, 784225, 784224Y, 784225Y
6. CPU ARCHITECTURE
6.1 Memory Space
A memory space of 1 Mbyte can be accessed. Mapping of the internal data area (special function registers and
internal RAM) can be specified the LOCATION instruction. The LOCATION instruction must be always executed
after RESET cancellation, and must not be used more than once.
(1) When LOCATION 0H instruction is executed
• Internal memory
The internal data area and internal ROM area are mapped as follows:
Part Number
µPD784224,
µPD784224Y
µPD784225,
µPD784225Y
Internal Data Area
0F100H to 0FFFFH
0EE00H to 0FFFFH
Internal ROM Area
00000H to 0F0FFH
10000H to 17FFFH
00000H to 0EDFFH
10000H to 1FFFFH
Caution The following areas that overlap the internal data area of the internal ROM cannot be used when
the LOCATION 0H instruction is executed.
Part Number
µPD784224,
µPD784224Y
µPD784225,
µPD784225Y
Unusable Area
0F100H to 0FFFFH (3,840 bytes)
0EE00H to 0FFFFH (4,608 bytes)
• External memory
The external memory is accessed in external memory expansion mode.
(2) When LOCATION 0FH instruction is executed
• Internal memory
The internal data area and internal ROM area are mapped as follows:
Part Number
µPD784224,
µPD784224Y
µPD784225,
µPD784225Y
Internal Data Area
FF100H to FFFFFH
Internal ROM Area
00000H to 17FFFH
FEE00H to FFFFFH
00000H to 1FFFFH
• External memory
The external memory is accessed in external memory expansion mode.
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Data Sheet U12376EJ1V0DS00