EM73362
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
FUNCTION DESCRIPTIONS
PROGRAM ROM ( 3K X 8 bits )
3 K x 8 bits program ROM contains user's program and some fixed data.
The basic structure of program ROM can be divided into 4 parts.
1. Address 000h: Reset start address.
2. Address 002h - 00Ch : 5 kinds of interrupt service routine entry addresses.
3. Address 00Eh-086h : SCALL subroutine entry address, only available at 00Eh,016h,01Eh,026h, 02Eh,
036h, 03Eh, 046h, 04Eh, 056h, 05Eh, 066h, 06Eh, 076h, 07Eh, 086h.
4. Address 000h - 7FFh : LCALL subroutine entry address.
5. Address 000h - BFFh : Except used as above function, the other region can be used as user's program region.
address
000h
002h
3072 x 8 bits
Reset start address
INT0; External interrupt service toutine entry address
004h
006h
008h
00Ah
00Ch
00Eh
086h
TRGA; Timer/counter A interrupt service routine entry address
TRGB; Timer/counter B interrupt service routine entry address
TBI; Time base interrupt service routine entry address
INT1; External interrupt service routine entry address
SCALL, subroutine call entry address
.
.
.
BFFh
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".
* This specification are subject to be changed without notice.
4
10.8.2001
ELAN [ ELAN MICROELECTRONICS CORP ]
