HT45F23 datasheet(30/152 Pages) HOLTEK

30 / 152 page

Bank Pointer

- BP

The Data Memory is divided into two Banks, known as Bank 0 and Bank 1. A Bank Pointer, which is

bit 0 of the Bank Pointer register is used to select the required Data Memory bank. Only data in Bank 0

can be directly addressed as data in Bank 1 must be indirectly addressed using Memory Pointer MP1

and Indirect Addressing Register IAR1. Using Memory Pointer MP0 and Indirect Addressing Register

IAR0 will always access data from Bank 0, irrespective of the value of the Bank Pointer. Memory

Pointer MP1 and Indirect Addressing Register IAR1 can indirectly address data in either Bank 0 or

Bank 1 depending upon the value of the Bank Pointer.

The Data Memory is initialised to Bank 0 after a reset, except for the WDT time-out reset in the

Idle/Sleep Mode, in which case, the Data Memory bank remains unaffected. It should be noted that

Special Function Data Memory is not affected by the bank selection, which means that the Special

Function Registers can be accessed from within either Bank 0 or Bank 1. Directly addressing the Data

Memory will always result in Bank 0 being accessed irrespective of the value of the Bank Pointer.

BP 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

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

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 programmers by locating it within the Special Purpose area of the Data Memory. By

manipulating this register, direct jumps to other program locations are easily implemented. Loading a

value directly into this PCL register will cause a jump to the specified Program Memory location.

However, as the register is only 8-bit wide, only jumps within the current Program Memory page are

permitted. When such operations are used, note that a dummy cycle will be inserted.

Look-up Table Registers

- TBLP, TBLH

These three special function registers are used to control operation of the look-up table which is stored

in the Program Memory. TBLP is the table pointer and indicates the location where the table data is

located. The value must be setup before any table read commands are executed. Their value can be

changed, for example using the

²INC² or ²DEC² instructions, allowing 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

Rev. 1.20

September 15, 2011

HT45F23/HT45F43

8-Bit Flash MCU with Op Amps & Comparators

HT45F23 Datasheet(PDF) 30 Page - Holtek Semiconductor Inc

HT45F23 Datasheet(HTML) 30 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