BS2824 Holtek Semiconductor Inc., BS2824 Datasheet - Page 18

• Manufacturer Part Number: BS2824
• Description: Touch Key Mcu
• Manufacturer: Holtek Semiconductor Inc.

BS2824/BS2854/BS2868
Touch Key MCU
Data Memory
Rev. 1.00
tempreg1 db ?
tempreg2 db ?
mov a,06h
tblp,a
tabrdl
dec tblp
tabrdl
org 700h
dc
Structure
Table Read Program Example
:
:
:
:
:
:
00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh
:
:
tempreg1
tempreg2
The Data Memory is a volatile area of 8-bit wide RAM internal memory and is the location where
temporary information is stored.
Divided into two sections, the first of these is an area of RAM where special function registers are
located. These registers have fixed locations and are necessary for correct operation of the device.
Many of these registers can be read from and written to directly under program control, however, some
remain protected from user manipulation. The second area of Data Memory is reserved for general
purpose use. All locations within this area are read and write accessible under program control.
The two sections of Data Memory, the Special Purpose and General Purpose Data Memory are located
at consecutive locations. All are implemented in RAM and are 8 bits wide but the length of each
memory section is dictated by the type of microcontroller chosen. The start address of the Data
Memory for all devices is the address 00H .
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 SET [m].i and CLR [m].i 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.
; temporary register #1
; temporary register #2
; initialise table pointer - note that this address is referenced
; to the last page or present page
; transfers value in table referenced by table pointer
; to tempregl
; data at prog. memory address 706H transferred to
; tempreg1 and TBLH
; reduce value of table pointer by one
; transfers value in table referenced by table pointer
; to tempreg2
; data at prog.memory address 705H transferred to
; tempreg2 and TBLH
; in this example the data 1AH is transferred to
; tempreg1 and data 0FH to register tempreg2
; the value 00H will be transferred to the high byte register TBLH
; sets initial address of last page
BS2824, BS2854
BS2868
Device
18
Capacity
224 8
96 8
Banks
0, 1
January 27, 2010