10

* This specification are subject to be changed without notice.

EM73P982

EM73P982

EM73P982

EM73P982

EM73P982

4-BIT MICROCONTROLLER

4-BIT MICROCONTROLLER

4-BIT MICROCONTROLLER

4-BIT MICROCONTROLLER

4-BIT MICROCONTROLLER

12.25.2001

B

XA2

:

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

BANK 2

XB1 :

:

:

BXB

:

XB2 :

:

B

XB2

:

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

BANK 3

XC1 :

:

:

BXC

:

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

LDAX

LDAX

LDAX

LDAX

Acc

Acc

Acc

Acc

Acc

←

←

←

←

← ROM[DP]

ROM[DP]

ROM[DP]

ROM[DP]

ROM[DP]

L

L

L

L

L

LDAXI

LDAXI

LDAXI

LDAXI

LDAXI

Acc

Acc

Acc

Acc

Acc

←

←

←

←

← ROM[DP]

ROM[DP]

ROM[DP]

ROM[DP]

ROM[DP]

H

H

H

H

,DP+1

,DP+1

,DP+1

,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

; [DP]

STADPM

; [DP]

STADPH

; [DP]

:

LDL #00h

;

LDH #03h

;

OUT #00H,P3

;

LDAX

; ACC

← 6h

STAMI

; RAM[30]

← 6h

LDAXI

; ACC

← 5h

STAM

; RAM[31]

← 5h

;

ORG 1777h

DATA 56h

;

DATA RAM ( 372-nibble )

DATA RAM ( 372-nibble )

DATA RAM ( 372-nibble )

DATA RAM ( 372-nibble )

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.