EM78P259N/260N

8-Bit Microprocessor with OTP ROM

6.4.1 Usage of Port 5 Input Change Wake-up/Interrupt Function

(1) Wake-up

(2) Wake-up and Interrupt

(a)Before Sleep

1.Disable WDT

2.Read I/O Port 5 (MOV R5,R5)

3.Execute "ENI" or "DISI"

4.Enable wake-up bit (Set RE ICWE =1)

5.Execute "SLEP" instruction

(b)After wake-up

→ Next instruction

(a)Before Sleep

1.Disable WDT

2.Read I/O Port 5 (MOV R5,R5)

3.Execute "ENI" or "DISI"

4.Enable wake-up bit (Set RE ICWE =1)

5.Enable interrupt (Set IOCF0 ICIE =1)

6.Execute "SLEP" instruction

(b)After wake-up

1.IF "ENI" → Interrupt vector (006H)

2.IF "DISI" → Next instruction

(3) Interrupt

(a)Before Port 5 pin change

1.Read I/O Port 5 (MOV R5,R5)

2.Execute "ENI" or "DISI"

3.Enable interrupt (Set IOCF0 ICIE =1)

(b)After Port 5 pin changed (interrupt)

1.IF "ENI" → Interrupt vector (006H)

2.IF "DISI" → Next instruction

6.5Reset and Wake-up

6.5.1 Reset and Wake-up Operation

A reset is initiated by one of the following events:

1.Power-on reset

2./RESET pin input "low"

3.WDT time-out (if enabled).

The device is kept under reset condition for a period of approximately 18ms3 (except in LXT mode) after the reset is detected. When in LXT mode, the reset time is 500ms. Two choices (18ms3 or 4.5ms4) are available for WDT-time out period. Once a reset occurs, the following functions are performed (the initial Address is 000h):

„The oscillator continues running, or will be started (if in sleep mode)

„The Program Counter (R2) is set to all "0"

3

4

VDD=5V, WDT Time-out period = 16.5ms ± 30%. VDD=3V, WDT Time-out period = 18ms ± 30%.

VDD=5V, WDT Time-out period = 4.2ms ± 30%. VDD=3V, WDT Time-out period = 4.5ms ± 30%.

Product Specification (V1.2) 05.18.2007

• 31

(This specification is subject to change without further notice)

Page 37
Image 37
IBM EM78P259N/260N manual Usage of Port 5 Input Change Wake-up/Interrupt Function, Reset and Wake-up Operation