HT45FM2C View Datasheet(PDF) - Holtek Semiconductor
Part Name
Description
MFG CO.
'HT45FM2C' PDF : 171 Pages View PDF
HT45FM2C
Preliminary
Brushless DC Motor Flash Type 8-Bit MCU
Flash Program Memory
The Program Memory is the location where the user code or program is stored. For this device 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, this Flash device 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 of 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.
Special Vectors
Within the Program Memory, certain locations are reserved for the reset and interrupts. The location
000H is reserved for use by this device reset for program initialisation. After a device reset is
initiated, the program will jump to this location and begin execution.
000H
R eset
004H
In te rru p t
02C H
V e c to r
FFFH
1 5 b its
Program Memory Structure
Look-up Table
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 "TABRDC [m]" or "TABRDL [m]" 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 “0”.
The accompanying diagram illustrates the addressing data flow of the look-up table.
Lastpage or
T B H P R e g is te r
T B L P R e g is te r
P ro g ra m M e m o ry
D a ta
1 5 b its
Rev. 1.10
R e g is te r T B L H
H ig h B y te
21
U s e r S e le c te d
R e g is te r
L o w B y te
May 30, 2012
Share Link: 
