EM73P361A
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
User's program and fixed data are stored in the program ROM. User's program is according the PC value
to send next executed instruction code. Fixed data can be read out by table-look-up instruction.
Table-look-up instruction is depended on the Data Pointer ( DP ) to indicate to ROM address, then to get the
ROM code data.
LDAX
Acc ← ROM[DP]L
LDAXI
Acc ← ROM[DP]H,DP+1
DP is a 12-bit data register which can store the program ROM address to be the pointer for the ROM code data.
First, user load ROM address into DP by instruction "STADPL, STADPM, STADPH", then user can get the
lower nibble of ROM code data by instruction "LDAX" and higher nibble by instruction "LDAXI".
PROGRAM EXAMPLE: Read out the ROM code of address 777h by table-look-up instruction.
LDIA #07h;
STADPL ; [DP]L ← 07h
STADPM ; [DP]M ← 07h
STADPH
:
; [DP]H ← 07h, Load DP=777h
LDL #00h;
LDH #03h;
LDAX
STAMI
LDAXI
STAM
;
; ACC ← 6h
; RAM[30] ← 6h
; ACC ← 5h
; RAM[31] ← 5h
ORG 777h
DATA 56h;
:
DATA RAM ( 52-nibble )
There is total 52 - nibble data RAM from address 00 to 33h
Data RAM includes 3 parts: zero page region, stacks and data area.
Increment
Address
00h - 0Fh
10h - 1Fh
20h - 2Fh
Level 0
Level 4
Level 8
Level 12
Level 1
Level 5
Level 9
Level 2
Level 6
Level 10
Level 3
Level 7
Level 11
30h - 33h
Stack
Zero-page
ZERO- PAGE:
From 00h to 0Fh is the location of zero-page. It is used as the pointer in zero -page addressing mode for the
instruction of "STD #k,y; ADD #k,y; CLR y,b; CMP k,y".
PROGRAM EXAMPLE: To wirte immediate data "07h" to address "03h" of RAM and to clear bit 2 of RAM.
STD #07h, 03h ; RAM[03] ← 07h
CLR 0Eh,2 ; RAM[0Eh]2 ←0
STACK:
There are 13 - level (maximum) stack for user using for subroutine (including interrupt and CALL). User
can assign any level be the starting stack by giving the level number to stack pointer (SP).
* This specification are subject to be changed without notice.
12.17.2001
6
ELAN [ ELAN MICROELECTRONICS CORP ]
