Samsung S3F84B8 Design Manual page 23

S3F84B8_ALL-IN-ONE IH COOKER_AN_REV 0.00
Figure 3-3 shows the flow chart of CMP1/2 interrupt service routine. Due to the cooperation of IH-PWM and
comparators integrated in S3F84B8, only a few jobs need to be done in the ISR.
NOTE: When hard lock happens, the PWM returns to the safe value immediately.
When soft lock happens. The PWM returns to the safe value immediately for the current PWM cycle. And the
PWMDATA will be reloaded as PWMPDATA, usually a smaller one, from the next cycle on.
IGBT temp < 55
Figure 3-4 shows the workflow of FAN and BUZ. FAN is always on as the IH cooker is generating heat. Even
when the device is powered off by manually setting or system protection, it is still on as long as the IGBT
temperature is higher than 55 ℃, in order to prevent the cooker from hot temperature damage.
Buzzer is mainly used for information indication. Besides the first beaming at power on, it only gives alarm when
some error lasts for 2sec or no pan is detected after trying 30 times
CMP1INT ISR (hard lock)
For surge protection
Start
Clr pending bit
Set P0.4(PWM) to input without pull-up R
PWMCON = 0
End
Figure 3-3
FAN work flow
Start
N
Power flag = 0?
Y
N
Y
Fan Off Fan On
Figure 3-4
CMP2INT ISR (soft lock)
For IGBT over voltage protection
Not mandatory
Interrupt Service Routine Diagram
BUZ work flow
Start
Beaming for 0.2s
N
Power flag = 1?
Y
Pan flag = 1?
Y
No pan detected?
Y
Beaming for 0.2s
Fan and BUZ Workflow
3-3
3 SOFTWARE IMPLEMENTATION
Start
Clr pending bit
End
N
N
Error lasts for 2s?
Y