Holtek HT46R22, Handbook

Page: 32 / 162

Note
Most of the Data Memory bits can be directly manipulated using the
²
SET [m].i
²
and
²
CLR [m].i
²
with the exception of a few dedicated bits. The Data Memory can also be accessed through the
memory pointer register MP.
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 program for both read and
write operations. By using the
²
SET [m].i
²
and
²
CLR [m].i
²
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.
Note The 384 bytes of General Purpose Data Memory in the HT46R24/HT46C24 are stored in two indi-
vidual memory banks. Before reading from or writing to the General Purpose Data Memory it is es-
sential to first ensure that the correct Data Memory bank is selected by setting up the Bank
Pointer. Bank 1 can only be addressed indirectly using the memory pointer MP1 and indirect ad-
dressing register IAR1.
Chapter 1 Hardware Structure
23
H T 4 6 R 2 2
H T 4 6 C 2 2
H T 4 6 R 2 3
H T 4 6 C 2 3
H T 4 6 R 2 4
H T 4 6 C 2 4
4 0 H
7 F H
4 0 H
8 0 H
7 F H
4 0 H
F F H
4 0 H
F F H
7 F H
8 0 H
7 F H
B a n k 0
B a n k 1
H T 4 6 R 4 7
H T 4 6 C 4 7
G e n e r a l P u r p o s e
D a t a M e m o r y
S p e c i a l P u r p o s e
D a t a M e m o r y
0 0 H
4 0 H
7 F H / F F H
3 F H