EM78P258N
8-Bit Microprocessor with OTP ROM
6.5.2 The T and P Status under STATUS (R3) Register
A RESET condition is initiated by one of the following events:
1. Power-on reset
2. /RESET pin input "low"
3. WDT time-out (if enabled).
The values of RST, T, and P as listed in the table below, are used to check how the
processor wakes up.
Reset Type
RST
T
P
Power-on
0
0
0
0
0
1
1
*P
1
1
*P
0
/RESET during Operating mode
/RESET wake-up during SLEEP mode
WDT during Operating mode
0
1
WDT wake-up during SLEEP mode
Wake-up on pin change during SLEEP mode
0
0
1
0
*P: Previous status before reset
The following shows the events that may affect the status of T and P.
Event
RST
T
P
Power-on
0
*P
0
1
1
0
1
1
1
1
WDTC instruction
WDT time-out
SLEP instruction
*P
0
*P
1
Wake-up on pin changed during SLEEP mode
0
*P: Previous value before reset
6.6 Interrupt
The EM78P258N has five interrupts as listed below:
1. TCC, TCCA, TCCB, TCCC overflow interrupt
2. Port 5 Input Status Change Interrupt
3. External interrupt [(P60, /INT) pin]
4. Analog to Digital conversion completed
5. IR/PWM underflow interrupt
Before the Port 5 Input Status Change Interrupt is enabled, reading Port 5 (e.g. "MOV
R5,R5") is necessary. Each Port 5 pin will have this feature if its status changes. The
Port 5 Input Status Change Interrupt will wake-up the EM78P258N from the sleep
mode if it is enabled prior to going into the sleep mode by executing SLEP instruction.
When wake-up occurs, the controller will continue to execute program in-line if the
global interrupt is disabled. If enabled, the global interrupt will branch out to the
interrupt vector 006H.
Product Specification (V1.0) 06.16.2005
• 39
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
