EM73866 Просмотр технического описания (PDF) - ELAN Microelectronics

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EM73866

4-BIT MICRO-CONTROLLER FOR LCD PRODUCT

ELAN Microelectronics 

EM73866

4-BIT MICRO-CONTROLLER FOR LCD PRODUCT

The bank is selected by P9.3. When P9.3 is cleared to "0", the bank 0 is selected. When P9.3 is set to "1", the bank

1 is selected.

There are 3 addressing mode to access the data memory, namely -

(1) Indirect addressing mode:

The address in the certain bank is specified by the HL registers.

P9.3 HR LR

RAM address

PROGRAM EXAMPLE: Load the data of RAM address "143h" to RAM address "032h".

SEP P9,3

; P9.3← 1

LDL #3h

; LR← 3

LDH #4h

; HR← 4

LDAM

; Acc← RAM[143h]

CLP P9,3

; P9.3← 0

LDL #2h

; LR← 2

LDH #3h

; HR← 3

STAM

; RAM[032h]← Acc

(2) Direct addressing mode:

The address in the bank is directly specified by 8 bits code of the second byte in the instruction field.

instruction field

xxxx xxxx

P9.3

RAM address

xxxx xxxx

PROGRAM EXAMPLE: Load the data of RAM address "143h" to RAM address "023h".

SEP P9,3

; P9.3← 1

LDA 43h

; Acc← RAM[143h]

CLP P9,3

; P9.3← 0

STA 23h

; RAM[023h]← Acc

(3) Zero-page addressing mode:

The address is the lower 4 bits code of the second byte in the instruction field.This kind of instructions are

only available for the zero page. Area in bank0, even the P9.3 is set.

instruction field

yyyy

RAM address 0 0000 yyyy

PROGRAM EXAMPLE: Write immediate "0Fh" to RAM address "005h".

STD #0Fh, 05h

; RAM[05h]← 0Fh

* This specification are subject to be changed without notice.

12.29.1999 7

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