SM5964BW44JP 参数 Datasheet PDF下载

SM5964B

8-Bit Micro-controller

64KB with ISP Flash

& 1KB RAM embedded

Mnemonic: SCONF

7

6

WDR

-

Address: BFh

0

Reset

ALEI

02H

5

-

4

PDWUE

3

-

2

ISPE

1

OME

OME: On-chip 768B expanded RAM enable bit.

Set 1 to enable on-chip 768B expanded RAM access.

There are two methods to access on-chip 768 bytes of expanded RAM. The first one is to use MOVX instruction

either by MOVX @DPTR or by MOVX @Ri. The other is to use a specific addressing bank switching scheme

combined with direct addressing MOV instruction.

Method 1 : By MOVX instruction

The 768 bytes on-chip expanded RAM can be accessed by MOVX instruction with OME bit in SCONF register

enabled. If MOVX @DPTR is used, the address range larger than 768B will force to access external data memory

automatically. If OME is disabled, IC will always access external data memory. OME is 1 in default setting.

The 768 bytes of on-chip expanded RAM can also be accessed by MOVX @Ri instruction. The content in Ri is

concatenated with RAMS1 and RAMS0 bit in RCON register in order to address on-chip 768bytes expanded RAM

and off-chip RAM totally up to 64KB memory range.

RAMS1 and RAMS0 bit in RCON register is the 256B bank selection while using MOVX @Ri to access expanded

RAM once OME bit in SCONF register is set.

Mnemonic: RCON

7

6

-

-

OME

1

1

1

1

0

RAMS1

0

0

1

1

x

RAMS0

0

1

0

1

Address: 85h

0

Reset

RAMS0

00H

Note

5

-

4

-

3

-

2

-

1

RAMS1

Mapped on-chip expanded RAM address

$0000 - $00FF

$0100 - $01FF

$0200 - $02FF

-

Mapped to off-chip RAM

address {P2 , Ri}

Mapped to off-chip RAM

x

-

address {P2 , Ri}

Table 3-1 : Mapped address for on-chip expanded RAM

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

ISSFD-M081

Ver A SM5964B 3/7/2014

- 19 -