HT66F03C datasheet(21/142 Pages) HOLTEK

21 / 142 page

HT66F03C/HT66F04C/HT68F03C/HT68F04C

Rev. 0.00

February 26, 2010

Preliminary

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

76543210

Name

¾¾¾¾¾¾¾

DMBP0

R/W

¾¾¾¾¾¾¾

R/W

POR

¾¾¾¾¾¾¾

Bit7~1

Unimplemented, read as

²0²

Bit 0

DMBP0: Select Data Memory Banks

0: Bank 0

1: Bank 1

HT66F03C Datasheet(PDF) 21 Page - Holtek Semiconductor Inc

HT66F03C Datasheet(HTML) 21 Page - Holtek Semiconductor Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL