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.
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
²
TABRD[m]
²
or
²
TABRDL[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
²
0
²
.
The accompanying diagram illustrates the addressing data flow of the look-up table.
BS83B08-3/B12-3/B16-3/B16G-3/C24-3
8-Bit Touch Key Flash MCU
Rev. 1.50
21
April 28, 2020
R e g i s t e r T B L H
U s e r S e l e c t e d
R e g i s t e r
H i g h B y t e
L o w B y t e
T B L P R e g i s t e r
D a t a
A
d
d
re
ss
1 5 o r 1 6 b i t s
P r o g r a m M e m o r y
L a s t p a g e o r
T B H P R e g i s t e r
Instruction
Table Location Bits
b11
b10
b9
b8
b7
b6
b5
b4
b3
b2
b1
b0
TABRDC [m]
PC11
PC10
PC9
PC8
@7
@6
@5
@4
@3
@2
@1
@0
TABRDL [m]
1
1
1
1
@7
@6
@5
@4
@3
@2
@1
@0
Table Location
Note:
PC11~PC8: Current Program Counter bits
@7~@0: Table Pointer TBLP bits
For the BS83B08-3, BS83B12-3 and BS83B16-3/BS83B16G-3, the Table address location is 11 bits, i.e. from
b10~b0.
For the BS83C24-3, the Table address location is 12 bits, i.e. from b11~b0