S3C72G9 Samsung semiconductor, S3C72G9 Datasheet - Page 91

• Manufacturer Part Number: S3C72G9
• Description: The S3C72G9 single-chip CMOS microcontroller has been designed for high performance using Samsungs newest 4-bit CPU core/ SAM47 (Samsung Arrangeable M
• Manufacturer: Samsung semiconductor

 

VENTn
Operation:
Description:
dst
EMB (0,1)
ERB (0,1)
ADR
The VENT instruction loads the contents of the enable memory bank flag (EMB) and enable
register bank flag (ERB) into the respective vector addresses. It then points the interrupt service
routine to the corresponding branching locations. The program counter is loaded automatically
with the respective vector addresses which indicate the starting address of the respective vector
interrupt service routines.
The EMB and ERB flags should be modified using VENT before the vector interrupts are
acknowledged. Then, when an interrupt is generated, the EMB and ERB values of the previous
routine are automatically pushed onto the stack and then popped back when the routine is
completed.
After the return from interrupt (IRET) you do not need to set the EMB and ERB values again.
Instead, use BITR and BITS to clear these values in your program routine.
The starting addresses for vector interrupts and reset operations are pointed to by the VENTn
instruction. These starting addresses must be located in ROM ranges 0000H-3FFFH. Generally,
the VENTn instructions are coded starting at location 0000H.
The format for VENT instructions is as follows:
EMB
ERB
PC
n = device-specific module address code (n = 0-n)
EMB (0,1)
ERB (0,1)
ADR
Operand
Operand
VENTn
ADDR (address to branch
d2 ("0" or "1")
d1 ("0" or "1")
Load enable memory bank flag (EMB) and the enable
register bank flag (ERB) and program counter to
vector address, then branch to the corresponding
location.
a7
M
E
B
d1,d2,ADDR
a6
R
E
B
a13 a12 a11 a10
a5
Binary Code
Operation Summary
a4
a3


a2
a9
a1
a8
a0
ROM (2 x n) 7-6
ROM (2 x n) 5-4
ROM (2 x n) 3-0
ROM (2 x n + 1) 7-0
(n = 0, 1, 2, 3, 4, 5, 6, 7)
Operation Notation

 


Bytes
2
EMB, ERB
PC13-12
PC11-8
PC7-0
Cycles
2