s3c72m9 Samsung Semiconductor, Inc., s3c72m9 Datasheet - Page 29

• Manufacturer Part Number: s3c72m9
• Description: The S3c72m5/s3c72m7/s3c72m9 Single-chip Cmos Microcontroller Has Been Designed For High Performance Using Samsung S
• Manufacturer: Samsung Semiconductor, Inc.

S3C72M5/C72M7/C72M9/P72M9 (Preliminary Spec)
F
The following examples show the correct programming method for selecting working register area:
1. When ERB = "0":
VENT2
;
INT0
The POP instructions execute alternately with the PUSH instructions. If an SMB n instruction is used in an interrupt
service routine, a PUSH and POP SB instruction must be used to store and restore the current SMB and SRB
values, as shown in Example 2 below.
2. When ERB = "1":
VENT2
;
INT0
PROGRAMMING TIP — Selecting the Working Register Area
1,0,INT0
PUSH
SRB
PUSH
PUSH
PUSH
PUSH
SMB
LD
LD
LD
INCS
LD
LD
POP
POP
POP
POP
POP
IRET
1,1,INT0
PUSH
SRB
SMB
LD
LD
LD
INCS
LD
LD
POP
IRET
SB
2
HL
WX
YZ
EA
0
EA,#00H
80H,EA
HL,#40H
HL
WX,EA
YZ,EA
EA
YZ
WX
HL
SB
SB
2
0
EA,#00H
80H,EA
HL,#40H
HL
WX,EA
YZ,EA
SB
; EMB
; PUSH current SMB, SRB
; Instruction does not execute because ERB = "0"
; PUSH HL register contents to stack
; PUSH WX register contents to stack
; PUSH YZ register contents to stack
; PUSH EA register contents to stack
; POP EA register contents from stack
; POP YZ register contents from stack
; POP WX register contents from stack
; POP HL register contents from stack
; POP current SMB, SRB
; EMB
; Store current SMB, SRB
; Select register bank 2 because of ERB = "1"
; Restore SMB, SRB
1, ERB
1, ERB
0, Jump to INT0 address
1, Jump to INT0 address
ADDRESS SPACES
2-13