uPD789871 Subseries 8-Bit Single-Chip Microcontrollers PUM
uPD789871 Subseries 8-Bit Single-Chip Microcontrollers PUM
uPD789871 Subseries 8-Bit Single-Chip Microcontrollers PUM
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34<br />
CHAPTER 3 CPU ARCHITECTURE<br />
3.1.1 Internal program memory space<br />
The internal program memory space stores programs and table data. This space is usually addressed by the<br />
program counter (PC).<br />
The µPD789871 <strong>Subseries</strong> provides the following internal ROMs (or flash memory) containing the following<br />
capacities.<br />
Table 3-1. Internal ROM Capacity<br />
Part Number Internal ROM<br />
Preliminary User’s Manual U14938EJ1V0UM<br />
Structure Capacity<br />
µPD789870 Mask ROM 4,096 × 8 bits<br />
µPD789871 8,192 × 8 bits<br />
µPD78F9872 Flash memory 16,384 × 8 bits<br />
The following areas are allocated to the internal program memory space:<br />
(1) Vector table area<br />
A 28-byte area of addresses 0000H to 001BH is reserved as a vector table area. This area stores program<br />
start addresses to be used when branching by the RESET input or an interrupt request generation. Of a 16bit<br />
program address, the lower 8 bits are stored in an even address, and the higher 8 bits are stored in an<br />
odd address.<br />
Table 3-2. Vector Table<br />
Vector Table Address Interrupt Request Vector Table Address Interrupt Request<br />
0000H RESET input 0010H INTKS<br />
0004H INTWDT 0012H INTCSI10<br />
0006H INTP0 0014H INTTM80<br />
0008H INTP1 0016H INTTM81<br />
000AH INTTM50 0018H INTWT<br />
000CH INTTM51 001AH INTWTI<br />
000EH INTTM52<br />
(2) CALLT instruction table area<br />
In a 64-byte area of addresses 0040H to 007FH, the subroutine entry address of a 1-byte call instruction<br />
(CALLT) can be stored.
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