HT56R66 datasheet(21/104 Pages) HOLTEK

21 / 104 page

HT56R66/HT56R666

Rev. 1.10

September 8, 2009

General Purpose Data Memory

All microcontroller programs require an area of

read/write memory where temporary data can be stored

and retrieved for use later. It is this area of RAM memory

that is known as General Purpose Data Memory. This

area of Data Memory is fully accessible by the user pro-

gram for both read and write operations. By using the

²SET [m].i² and ²CLR [m].i² instructions individual bits

can be set or reset under program control giving the

user a large range of flexibility for bit manipulation in the

Data Memory. For devices with larger Data Memory ca-

pacities, the General Purpose Data Memory, in addition

to being located in Bank 0, is also stored in Banks 2 to

12, the actual number of banks present depends upon

the device selected.

Special Purpose Data Memory

This area of Data Memory is where registers, necessary

for the correct operation of the microcontroller, are

stored. Most of the registers are both read and write type

but some are protected and are read only, the details of

which are located under the relevant Special Function

any read instruction to these addresses will return the

value

²00H². The Special Function registers are

mapped into all banks and can therefore be accessed

from any bank location.

Display Memory

The data to be displayed on the LCD or LED display is

stored in an area of fully accessible Data Memory. By

writing to this area of RAM, the display output can be di-

rectly controlled by the application program. As this

Memory exists in Bank 1, but have addresses which

map into the General Purpose Data Memory, it is neces-

sary to first ensure that the Bank Pointer is set to the

value 01H before accessing the Display Memory. The

Display Memory can only be accessed indirectly using

the Memory Pointer MP1 and the indirect addressing

access the Display Memory, if any addresses with a

value less than 40H are read, the Special Purpose

Memory in Bank 0 will be accessed. Also, if the Bank

Pointer is set to Bank 1, if any addresses higher than the

last address in Bank 1 are read, then a value of 00H will

be returned.

Special Function Registers

To ensure successful operation of the microcontroller,

certain internal registers are implemented in the Data

Memory area. These registers ensure correct operation

of internal functions such as timers, interrupts, etc., as

well as external functions such as I/O data control and

A/D converter operation. The location of these registers

within the Data Memory begins at the address 00H. Any

unused Data Memory locations between these special

0 0 H

0 1 H

0 2 H

0 3 H

0 4 H

0 5 H

0 6 H

0 7 H

0 8 H

0 9 H

0 A H

0 B H

0 C H

0 D H

0 E H

0 F H

1 0 H

1 1 H

1 2 H

1 3 H

1 4 H

1 5 H

1 6 H

1 7 H

1 8 H

1 9 H

1 A H

1 B H

1 C H

1 D H

1 E H

1 F H

2 0 H

2 1 H

2 2 H

2 3 H

2 4 H

2 5 H

2 6 H

2 7 H

2 8 H

2 9 H

2 A H

2 B H

2 C H

2 D H

2 E H

2 F H

3 0 H

3 1 H

3 2 H

3 3 H

3 4 H

3 5 H

3 6 H

3 7 H

3 8 H

3 9 H

3 A H

3 B H

3 C H

3 D H

3 E H

3 F H

H T 5 6 R 6 6

: U n u s e d R e a d a s " 0 0 "

I A R 0

M P 0

I A R 1

M P 1

B P

A C C

P C L

T B L P

T B L H

R T C C

S T A T U S

I N T C 0

T M R 0

T M R 0 C

T M R 1 H

T M R 1 L

T M R 1 C

P A

P A C

P B

P B C

P C

P C C

P D

P D C

P W M 0 L

P W M 0 H

P W M 1 L

P W M 1 H

I N T C 1

P W M 2 L

P W M 2 H

P W M 3 L

P W M 3 H

A D R L

A D R H

A D C R

A C S R

C L K M O D

P A W U

P A P U

P B P U

P C P U

P D P U

I N T E D G E

L C D C T R L

L C D O U T 1

L C D O U T 2

M I S C

M F I C 0

M F I C 1

S I M C T L 0

S I M C T L 1

S I M D R

S I M A R / S I M C T L 2

T M R 2

T M R 2 C

T M R 3

T M R 3 C

H T 5 6 R 6 6 6