UPD17230 Datasheet, PDF (12/92 Pages) NEC – 4-BIT SINGLE-CHIP MICROCONTROLLER FOR SMALL GENERAL-PURPOSE INFRARED REMOTE CONTROL TRANSMITTER

µPD17230, 17231, 17232, 17233, 17234, 17235, 17236
2. MEMORY SPACE
2.1 Program Counter (PC)
The program counter (PC) specifies an address of the program memory (ROM).
The program counter is an 11/12/13-bit binary counter and a 1-bit segment counter (SGR) as shown in Figure
2-1.
Its contents are initialized to address 0000H at reset.
Figure 2-1. Configuration of Program Counter
Page
MSB
LSB
SGR PC12 PC11 PC10 PC9
PC8
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
PC (µPD17230)
PC (µPD17231)
PC (µPD17232, 17233)
PC (µPD17234, 17235, 17236)
2.1.1 Segment register (SGR)
The segment register specifies a segment of the program memory.
Table 2-1 shows the relation between the segment register and program memory.
Table 2-1. Relation between Segment Register and Program Memory
Value of Segment Register
0
1
Segment of Program Memory
Segment 0
Segment 1
The segment register is set when the following instructions are executed:
• BR @AR
• CALL @AR
• SYSCAL entry
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Data Sheet U14360EJ1V0DS00