EM78P257
OTP ROM
Table 5 Usage of Port 5 Input Status Changed Wake-up/Interrupt Function
Usage of Port 5 input status changed Wake-up/Interrupt
(I) Wake-up from Port 5 Input Status Change
(a) Before SLEEP
(II) Port 5 Input Status Change Interrupt
1. Read I/O Port 5 (MOV R5,R5)
1. Disable WDT
2. Execute "ENI"
2. Read I/O Port 5 (MOV R5,R5)
3. Execute "ENI" or "DISI"
4. Enable interrupt (Set IOCF0.1)
5. Execute "SLEP" instruction
(b) After Wake-up
3. Enable interrupt (Set IOCF0.1)
4. IF Port 5 change (interrupt)
® Interrupt vector (3FEH)
1. IF "ENI" ® Interrupt vector (3FEH)
2. IF "DISI" ® Next instruction
4.5 RESET and Wake-up
1. RESET
A RESET is initiated by one of the following events-
(1) Power on reset;
(2) /RESET pin input "low", or
(3) Watch dog timer time-out (if enabled).
The device is kept in aRESET condition for a period of approximately 18ms1 or 1ms2 (one oscillator start-up timer
period) after the reset is detected. The initial address is 000h.Once the RESET occurs, the following events are
performed.
• The oscillator is running, or will be started.
• The Program Counter (R2) is set to all "0".
• All I/O port pins are configured as input mode (high-impedance state).
• The Watchdog timer and prescaler are cleared.
• When power is switched on, the upper 3 bits of R3 are cleared.
• The bits of the CONT register are set to all "1" except for the Bit 6 (INT flag).
• The bits of the IOCB0 register are set to all "1".
• The IOCC0 register is cleared.
• The bits of the IOCD0 register are set to all "1".
1 NOTE: VDD=5V, Setup time period = 15.4ms ± 30%.
VDD=3V, Setup time period = 17.6ms ± 30%.
2 NOTE: VDD=5V, Setup time period = 1.07ms ± 30%.
VDD=3V, Setup time period = 1.22ms ± 30%.
This specification is subject to change without prior notice.
32
07.27.2004 (V1.4)
ELAN [ ELAN MICROELECTRONICS CORP ]
