HT68F14 HOLTEK [Holtek Semiconductor Inc], HT68F14 Datasheet - Page 19

• Manufacturer Part Number: HT68F14
• Description: Enhanced I/O Flash Type MCU
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

HT68F13/HT68F14/HT68F15
Enhanced I/O Flash Type MCU
Flash Program Memory
Rev. 1.10
Structure
Special Vectors
Look-up Table
The Program Memory is the location where the user code or program is stored. For this device series
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.
The Program Memory has a capacity of 1K´14 bits to 4K´15 bits. 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.
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.
Any location within the Program Memory can be defined as a look-up table where programmers can
store fixed data. To use the look-up table, the table pointer must first be setup by placing the address of
the look up data to be retrieved in the table pointer register, TBLP and TBHP. These registers define the
total address of the look-up table.
After setting up the table pointer, the table data can be retrieved from the Program Memory using the
²TABRD[m]² or ²TABRDL[m]² instructions, respectively. When the instruction is executed, the
lower order table byte from the Program Memory will be transferred to the user defined Data Memory
register [m] as specified in the instruction. The higher order table data byte from the Program Memory
will be transferred to the TBLH special register. Any unused bits in this transferred higher order byte
will be read as ²0².
Program Memory Structure
HT68F20
HT68F30
HT68F40
Device
Capacity
1K´14
2K´15
4K´15
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February 9, 2011