Specifications subject to change without notice,contact your sales representatives for the most recent information.

7/26

Ver 2.1

SM79164 08/2006

SyncMOS Technologies International. Inc.

SM79164

FF

80

7F

00

FF

80

0EFF

0000

Higher 128 bytes (Access by

indirect addressing mode only)

SFR (Accessed by direct

addressing mode only)

Lower 128 bytes (Accessed by

direct & indirect addressing mode)

Expanded 3840 bytes RAM

(Accessed by direct external

addressing mode, by instruction

MOVX, or by Bank mapping

direct addressing mode)

On-chip expanded RAM address structure.

1.2.1 Data Memory - Lower 128 byte ($00 to $7F, Bank 0 & Bank 1)

Data Memory $00 to $FF is the same as 8052.

The address $00 to $7F can be accessed by direct and indirect addressing modes.

Address $00 to $1F is register area.

Address $20 to $2F is memory bit area.

Address $30 to $7F is for general memory area.

1.2.2 Data Memory - Higher 128 byte ($80 to $FF, Bank 2 & Bank 3)

The address $80 to $FF can be accessed by indirect addressing mode or by bank mapping direct addressing mode.

Address $80 to $FF is data area.

1.2.3 Data Memory - Expanded 3840 bytes ($0000 to $0EFF, Bank 4 ~ Bank 63)

From external address $0000 to $0EFF is the on-chip expanded RAM area, total 3840 bytes. This area can be accessed

by external direct addressing mode (by instruction MOVX) or by bank mapping direct addressing mode as described

below:

1.3 Bank mapping direct addressing mode

:

We provide RAM bank address ‘40H~7FH’ as mapping window which allow user access all the 4KB on-chip RAM through

this RAM bank address.

That means using direct addressing mode can access all the 4KB on-chip RAM. Please see next page for the mapping

mode table.

(OME = 1)