SM5964 Datasheet, PDF (8/28 Pages) SyncMOS Technologies,Inc – 8 - bit single chip microcontroller with 64KB flash & 1K byte RAM embedded

SyncMOS Technologies Inc.
July 2002
SM5964
1.3 Bank mapping direct addressing mode:
We provide RAM bank address ‘40H~7FH’ as mapping window which allow user access all the 1K on-chip RAM through
this RAM bank address.
BS3
BS2
BS1
BS0 040h~07fh map-
ping address
Note
0
0
0
0
000h~03fh
lower 128 byte RAM
0
0
0
1
040h~07fh
lower 128 byte RAM
0
0
1
0
080h~0bfh
higher 128 byte RAM
0
0
1
1
0c0h~0ffh
higher 128 byte RAM
0
1
0
0
0000h~003fh on-chip expanded 768 byte RAM
0
1
0
1
0040h~007fh on-chip expanded 768 byte RAM
0
1
1
0
0080h~00bfh on-chip expanded 768 byte RAM
0
1
1
1
00c0h~00ffh on-chip expanded 768 byte RAM
1
0
0
0
0100h~013fh on-chip expanded 768 byte RAM
1
0
0
1
0140h~017fh on-chip expanded 768 byte RAM
1
0
1
0
0180h~01bfh on-chip expanded 768 byte RAM
1
0
1
1
01c0h~01ffh on-chip expanded 768 byte RAM
1
1
0
0
0200h~023fh on-chip expanded 768 byte RAM
1
1
0
1
0240h~027fh on-chip expanded 768 byte RAM
1
1
1
0
0280h~02bfh on-chip expanded 768 byte RAM
1
1
1
1
02c0h~02ffh on-chip expanded 768 byte RAM
With this bank mapping scheme, user can access entire 1k byte on-chip RAM with direct addressing method. That means
using the window area ($040~$07F), user can access any bank (64 byte) data of 1k byte on-chip RAM space which is
selected by BS[0:3] of data bank control register (DBANK, $86).
For example, user write #30h to $101 address :
MOV DBANK, #88H
; set bank mapping $040~$07f to $0100~$013f
MOV A, #30H
; store #30H to A
MOV 41H, A
; write #30H to $0101 address
Data Bank Control Register (DBANK, $86)
bit-7
bit-0
Read :
Write :
BSE
Unused Unused Unused
BS3
BS2
BS1
BS0
Reset value :
0
*
*
*
0
0
0
1
Specifications subject to change without notice,contact your sales representatives for the most recent information.
8/28
Ver 1.0
PID 5964 07/02