UPD65 NEC [NEC], UPD65 Datasheet - Page 10

• Manufacturer Part Number: UPD65
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER FOR INFRARED REMOTE CONTROL TRANSMISSION
• Manufacturer: NEC [NEC]

2.4 Program Memory (ROM): 1002 steps
2.5 Data Memory (RAM): 32
memory is sometimes processed in 8-bit units. R0 can be used as the ROM data pointer.
10
The ROM consists of 10 bits per step, and is addressed by the program counter.
The program memory stores programs and table data, etc.
The 22 steps from 7EAH to 7FFH cannot be used in the test program area.
Note The unmounted area and test program area are so designed that a program or data placed in either of
The data memory, which is a static RAM consisting of 32
RF is also used as the ASR.
When reset, R0 is cleared to “00H” and R1 to RF retain the previous data (undefined when turning on the power).
3EAH
7EAH
3E9H
7E9H
7FFH
000H
them by mistake is returned to the 000H address.
Test program area
Unmounted area
(a)
10 bits
PD64A
Note
Note
2026 steps
4 Bits
Figure 2-3. Program Memory Map
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Data Sheet U14380EJ2V0DS00
10 bits ( PD64A)
10 bits ( PD65)
7EAH
3FFH
7E9H
7FFH
4 bits, is used to retain processed data. The data
000H
400H
Test program area
(b)
10 bits
PD65
Note
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PD64A, 65