sh66k33a SinoWealth Micro-Electronics Corp. Ltd, sh66k33a Datasheet - Page 8

• Manufacturer Part Number: sh66k33a
• Description: Mask 1k 4-bit Micro-controller
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

Port Interrupt
The PORTB, PORTC or PORTB, PORTC and PORTD are used as port interrupt sources. Since PORT I/O is a bit
programmable I/O, therefore only the input port can generate an external interrupt. Any transition from PORTB and PORTC
input pins from GND to V
high, PORTB, PORTC and PORTD as the port interrupt source. But further rising edge transitions cannot be able to make
interrupt request until all of the pins return to GND. The following is the port interrupt function block-diagram.
Port Interrupt PROGRAMMING NOTES:
If user wants to generate an interrupt when a rising edge from GND to V
1. Set the port as input port, fill port data register with “0” and avoid port floating.
2. Pull-low the port (Use external pull-low resistance or set PPULL to “1”).
3. Set port interrupt enable flag (Set IEP to “1” in port interrupt application.).
And further rising edge transition would not be able to make interrupt request until all of the pins return to GND in Port interrupt
application.
PORTC.n
PORTD.n
PORTC.n
PORTB.n
PORTB.n
DD
will generate an interrupt request (Default). When Code Option (Port interrupt source select) is
Note: n=0, 1, 2, 3
Note: n = 0, 1, 2, 3
PCCR.n
PBCR.n
PCCR.n
PDCR.n
PBCR.n
PORT Interrupt Block Diagram
Edge Detector
Edge Detector
8
Rising
Rising
Default : Port interrupt source select = 1
Default : Port interrupt source select = 0
PortB, PortC and PortD interrupt
DD
PortB and PortC interrupt
emerges in the port, the following must be executed.
IEP
IEP
IRQP
IRQP
Port Interrupt
Port Interrupt
SH66K33A