SM39A16M1U32 参数 Datasheet PDF下载

SM39A16M1

8-Bit Micro-controller

16KB with ISP Flash

& 1K+256B RAM embedded

3.2

Data Memory

The SM39A16M1 has 1K + 256B on-chip SRAM, 256B of it are the same as general 8052 internal memory structure

while the expanded 1K Bytes on-chip SRAM can be accessed by external memory addressing method ( by instruction

MOVX.). As shown in Fig. 3-2

03FF

FF

FF

Higher 128 Bytes (Accessed by

indirect addressing mode only)

80

7F

SFR (Accessed by direct addressing

mode only)

80

Expanded 1K Bytes

(Accessed by direct

external addressing mode

by instruction MOVX)

Lower 128 Bytes (Accessed by

direct & indirect addressing mode )

00

0000

Fig. 3-2: RAM architecture

3.3

Data memory - lower 128 byte (00h to 7Fh)

Data memory 00h to FFh is the same as 8052.

The address 00h to 7Fh can be accessed by direct and indirect addressing modes.

Address 00h to 1Fh is register area.

Address 20h to 2Fh is memory bit area.

Address 30h to 7Fh is for general memory area.

3.4

Data memory - higher 128 byte (80h to FFh)

The address 80h to FFh can be accessed by indirect addressing mode.

Address 80h to FFh is data area.

3.5

Data memory - Expanded 1K Bytes ( 0000h ~ 0x03FFh)

From external address 0000h to 03FFh is the on-chip expanded SRAM area, total 1K Bytes. This area can be

accessed by external direct addressing mode (by instruction MOVX). The address space of instruction MOVX @Ri, i=0,

1 is determined by RCON [7:0] of special function register $86 RCON (internal RAM control register). The default

setting of RCON [7:0] is 00h (page0). One page of data RAM is 256 bytes. When EMEN = 0, the internal 1K expanded

RAM is enabled.

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

ISSFD-M069

Ver C

SM39A16M1

7/31/2013

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