EM73982 Просмотр технического описания (PDF) - ELAN Microelectronics

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EM73982

4-BIT MICROCONTROLLER

ELAN Microelectronics 

EM73982

4-BIT MICROCONTROLLER

B

XA2

:

;--------------- -------------------- -------------------- -------------------- --

BANK 2

XB1 :

:

:

B

XB

:

XB2 :

:

B

XB2

:

;--------------- -------------------- -------------------- -------------------- --

BANK 3

XC1 :

:

:

B

XC

:

XC2 :

:

B

XC2

Fixed data can be read out by table-look-up instruction. Table-look-up instruction is depended on the Data

Pointer (DP) to indicate the ROM address, then to get the ROM code data :

LDAX

LDAXI

Acc ← ROM[DP]L

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".

To access DP (LDADPL, LDADPM, LDADPH, STADPL, STADPM, STADPH), user must switch RAM

at BANK0.

PROGRAM EXAMPLE: Read out the ROM code of address 1777h by table-look-up instruction.

LDIA #07h;

STADPL

STADPM

STADPH

:

LDL #00h

LDH #03h

OUT #00H,P3

LDAX

STAMI

LDAXI

STAM

;

ORG 1777h

DATA 56h

; [DP]L ← 07h

;

[DP]

M

←

07h

; [DP]H ← 07h, Load DP=777h

;

;

;

; ACC ← 6h

; RAM[30] ← 6h

; ACC ← 5h

; RAM[31] ← 5h

;

DATA RAM ( 372-nibble )

There is total 372 - nibble data RAM from address 000 to 17Fh

Data RAM includes 3 parts: zero page region, stacks and data area.

* This specification are subject to be changed without notice.

11.30.2001 10

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