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Standard 8051 8-Bit Flash MCU
HT85F2260/HT85F2270/HT85F2280
Arithmetic and Logic Unit –
ALU
Flash Program Memory
18
Flash Program Memory
The Program Memory is the location where the user code or program is stored. For these devices
the Program Memory is Flash type, which means it can be programmed and re-programmed
a large number of times, allowing the user the convenience of code modification on the same
device. By using the appropriate programming tools, these Flash devices offer users the flexibility
to conveniently debug and develop their applications while also offering a means of field
programming and updating.
Structure
The Program Memory has a capacity from 16K×8 to 64K×8. The Program Memory is addressed
by the Program Counter and also contains data, table information and interrupt entries. Table data,
which can be setup in any location within the Program Memory, is addressed by a separate table
pointer register.
Special Vectors
Within the Program Memory, certain locations are reserved for the reset and interrupts. The
location 000H is reserved for use by the device reset for program initialisation. After a device reset
is initiated, the program will jump to this location and begin execution.
3FFFH
Reset
0000H
HT85F2260
0003H
00ABH
HT85F2270 HT85F2280
Inte���pt
Vecto�
8 bits
8 bits
8 bits
Reset
Inte���pt
Vecto�
Reset
Inte���pt
Vecto�
7FFFH
FFFFH
Program Memory Structure