HT66F016 View Datasheet(PDF) - Holtek Semiconductor
Part Name
Description
MFG CO.
'HT66F016' PDF : 116 Pages View PDF
HT66F016/HT66F017/HT68F016/HT68F017
HT66F016R/HT66F017R/HT68F016R/HT68F017R
Bank Pointer - BP
For this series of devices, the Data Memory is divided
into two banks. Selecting the required Data Memory
area is achieved using the Bank Pointer. Bit 0 is used to
select Data Memory Banks 0~1.
The Data Memory is initialised to Bank 0 after a reset,
except for a WDT time-out reset in the Power Down
Mode, in which case, the Data Memory bank remains
unaffected. It should be noted that the Special Function
Data Memory is not affected by the bank selection,
which means that the Special Function Registers can be
accessed from within any bank. Directly addressing the
Data Memory will always result in Bank 0 being ac-
cessed irrespective of the value of the Bank Pointer. Ac-
cessing data from banks other than Bank 0 must be
implemented using indirect addressing.
Accumulator - ACC
The Accumulator is central to the operation of any
microcontroller and is closely related with operations
carried out by the ALU. The Accumulator is the place
where all intermediate results from the ALU are stored.
Without the Accumulator it would be necessary to write
the result of each calculation or logical operation such
as addition, subtraction, shift, etc., to the Data Memory
resulting in higher programming and timing overheads.
Data transfer operations usually involve the temporary
storage function of the Accumulator; for example, when
transferring data between one user defined register and
another, it is necessary to do this by passing the data
through the Accumulator as no direct transfer between
two registers is permitted.
Program Counter Low Register - PCL
To provide additional program control functions, the low
byte of the Program Counter is made accessible to pro-
grammers by locating it within the Special Purpose area
of the Data Memory. By manipulating this register, direct
jumps to other program locations are easily imple-
mented. Loading a value directly into this PCL register
will cause a jump to the specified Program Memory lo-
cation, however, as the register is only 8-bit wide, only
jumps within the current Program Memory page are per-
mitted. When such operations are used, note that a
dummy cycle will be inserted.
Look-up Table Registers - TBLP, TBHP, TBLH
These three special function registers are used to con-
trol operation of the look-up table which is stored in the
Program Memory. TBLP and TBHP are the table pointer
and indicates the location where the table data is lo-
cated. Their value must be setup before any table read
commands are executed. Their value can be changed,
for example using the ²INC² or ²DEC² instructions, al-
lowing for easy table data pointing and reading. TBLH is
the location where the high order byte of the table data is
stored after a table read data instruction has been exe-
cuted. Note that the lower order table data byte is trans-
ferred to a user defined location.
· Bank Pointer Register
Bit
7
6
5
4
3
2
1
0
Name
¾
¾
¾
¾
¾
¾
¾
DMBP0
R/W
¾
¾
¾
¾
¾
¾
¾
R/W
POR
¾
¾
¾
¾
¾
¾
¾
0
Bit 7 ~ 1
Bit 0
Unimplemented, read as ²0²
DMBP0: Select Data Memory Banks
0: Bank 0
1: Bank 1
Rev. 1.40
24
November 22, 2016
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