sh66l16a SinoWealth Micro-Electronics Corp. Ltd, sh66l16a Datasheet - Page 12

• Manufacturer Part Number: sh66l16a
• Description: 16k 4-bit Low Power Micro-controller With Lcd Driver
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

SH66L16A
PORTB, PORTC Interrupt
The PORTB and PORTC are used as the port interrupt sources. Following is the port interrupt function block-diagram.
IEP
PB.n
Falling
Port Interrupt
Edge Detector
PC.n
PBCR.n
PCCR.n
IRQP
Note: n = 0, 1, 2, 3
Port Interrupt (PBC INT) PROGRAMMING NOTES:
If user wants to generate an interrupt when a low level emerges on the port, the following must be executed.
1. Set the port as input port, fill port data register with “1” and avoid port floating.
2. Pull-high the port (Use external pull-high resistance or set PPULL to “1” and write “1” to the port data register).
In order to correctly return from the port interrupt-processing subroutine, the low level applying on the port must be
released before the relative IRQ flag clearing and IE resetting. Otherwise, it is possible to reenter the active interrupt.
External Interrupt
PORTA.0 is shared with external interrupt (Active low).
The external interrupt is available only when
1. Set the PORTA.0 as input port, fill port data register with “1” and avoid port floating.
2. Pull-high the PORTA.0 (Use external pull-high resistance or set PPULL to “1”).
In order to correctly return from the external (PORTA.0) interrupt-processing subroutine, the low level applying on the
PORTA.0 must be released before the relative IRQ flag clearing and IE resetting. Otherwise, it is possible to reenter
the active interrupt.
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