ePVP6800
VFD Controller
7.7.4 Wake-up from IDLE Mode
1. WDT time out
2. External interrupt
3. Internal interrupt like counters
All these cases requires you to enable the circuit before entering IDLE mode. All the registers values
are preserved when "SLEP" instruction is executed and restored after wake-up.
During execution of case 2 or 3, controller will wake up and jump to address 0x08 for interruption
sub-routine. After performing the sub-routine ("RETI" instruction), the program will jump to the next
instruction following the "SLEP" instruction.
7.8 Interrupts
RD, RF are the interrupt status registers which record the interrupt request in flag bit. IOCD,& IOCF
are their interrupt mask registers respectively. Global interrupt is enabled by ENI instruction and is
disabled by DISI instruction. When one of the interrupts (when enabled) is generated, it will cause the
next instruction to be fetched from address 008H. Once in the interrupt service routine, the source of
the interrupt can be determined by polling the flag bits in their respective (RD, RE, and RF) registers.
The interrupt flag bit must be cleared in the software before leaving the interrupt service routine and
enabling interrupts to avoid recursive interrupts.
7.9 Instruction Set
The Instruction set has the following features:
1. Every bit of any register can be set, cleared, or tested directly.
2. The I/O register can be treated as a general register. That is, the same instruction can operates on
I/O register.
The symbol "R" represents a register designator which specifies which one of the 64 registers
(including operational registers and general purpose registers) is to be utilized by the instruction. Bits
6 and 7 in R4 determine the selected register bank. "b'' represents a bit field designator which selects
the number of the bit located in the Register "R,” and affected by the operation. "k'' represents an 8 or
10-bit constant or literal value.
Status
Affected
Instruction
Cycle
Instruction Binary
HEX
0000
Mnemonic
NOP
Operation
No Operation
0 0000 0000 0000
0 0000 0000 0001
0 0000 0000 0010
0 0000 0000 0011
0 0000 0000 0100
0 0000 0000 rrrr
0 0000 0001 0000
0 0000 0001 0001
None
C
1
1
1
1
1
1
1
1
0001
0002
0003
0004
000r
0010
0011
DAA
Decimal Adjust A
A → CONT
CONTW
SLEP
WDTC
IOW R
ENI
None
T,P
0 → WDT, Stop oscillator
0 → WDT
T,P
A → IOCR
None
None
None
Enable Interrupt
Disable Interrupt
DISI
28 of 47 11. 28.2004 (V1.23)
This specification is subject to change without further notice.
ELAN [ ELAN MICROELECTRONICS CORP ]
