EM73MA89B
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
ry
limina
Pre
ZERO- PAGE:
From 000h to 00Fh is the zero-page location. It is used as the zero-page address mode pointer for the
instruction of "STD #k,y; ADD #k,y; CLR y,b; CMP k,y".
PROGRAM EXAMPLE: To write immediate data "07h" to RAM [03] and to clear bit 2 of RAM [0Eh].
STD #07h, 03h ; RAM[03]
←
07h
CLR 0Eh,2 ; RAM[0Eh]
2
←
0
STACK:
There are 13 - level (maximum) stack levels that user can use for subroutine (including interrupt and CALL).
User can assign any level be the starting stack by providing the level number to stack pointer (SP).
When an instruction (CALL or interrupt) is invoked, before enter the subroutine, the previous PC address
is saved into the stack until returned from those subroutines, the PC value is restored by the data saved in stack.
DATA AREA:
Except the area used by user's application, the whole RAM can be used as data area for storing and loading
general data.
ADDRESSING MODE
The 1012 nibble data memory consists of four banks (bank 0 ~ bank 3). There are 244x4 bits (address
000h~0F3h) in bank 0 and 768x4 bits (address 100h ~ 3FFh) in bank 1 ~ bank 3.
The bank is selected by P9.
P9
Initial value : * * 0 0
* * RBK
RBK RAM bank
0 0
Bank0
0 1
Bank1
1 0
Bank2
1 1
Bank3
The Data Memory consists of three Address mode, namely -
(1) Indirect addressing mode:
The address in the bank is specified by the HL registers.
P9(1,0)
HR
LR
RAM address
* This specification are subject to be changed without notice.
10.15.2002 (V1.3)
9
EMC [ ELAN MICROELECTRONICS CORP ]
