Toshiba TC9349AFG Manual

TC9349AFG2006-02-2454{ External Interrupt and Timer Counter FunctionsThere are two types of pin for external interrupt: INTR1 and INTR2. An interrupt request is issued on detection of theedge of the signal applied to pins INTR1 and INTR2, whether rising, falling or both. The interrupt input pins also combinethe functions of I/O port; break during backup; and, in the case of the INTR2 pin, PLL INH input pin.The timer counter is an 8-bit binary counter and has timer mode and pulse width measurement mode functions. In pulsewidth measurement mode, the pulse width input from the external interrupt pin (INTR1) is measured. This can be used forpurposes such as detecting the leader pulse of a remote control.1. External Interrupt FunctionThere are two types of pin for external interrupt, INTR1 and INTR2, and an interrupt request is issued on detection of theedge of these inputs. The inputs incorporate a Schmitt circuit and a noise canceller, the frequency of the CPU clock(low-speed oscillation clock: 75 kHz; high-speed oscillation clock: 300 ∼ 600 kHz) being used for the noise-filtering clock.Any pulse of less than 1 ~ 3 clocks of the CPU clock is removed as noise; and an interrupt is generated when a pulse at orover 1 ~ 3 clocks of the CPU clock (at the time of a 75 kHz oscillation: 13.3 ~ 40 μs) is input. Either the rising or the fallingedge, or both, can be selected for each pin.The pin used for the external interrupt function also serves as an I/O port. Interrupt will be permitted if edge selection isenabled through use of the external interrupt control port. The external interrupt input state can be read from the I/O port 4input data port (φK33), which is used in combination.The INTR1 pin is used in combination with the input pin of the pulse width measurement mode function of the timercounter. The INTR1 control port is also used to control the logical setting of the pulse.(Refer to the section on the timer counter.)The external interrupt of the INTR2 pin is selected together with the timer port interrupt. When external interrupt of theINTR2 pin is used, it is necessary to set the timer port. (Refer to the sections on the timer port and on changing the interruptfactor.) The program will branch to address 0001H if an INTR1 pin interrupt is received, to address 0002H if an INTR2 pininterrupt is received.Note: The function becomes effective when INH input function and break function are permitted on setting ofthe external interrupt function.Note: When interrupt is permitted, the I/O port 4 control port becomes invalid and is forced to change to aninput port.POS2 NEG2POS1 NEG1Y1 Y2 Y4 Y8INTR2 external interruption / Control of timer port interruptionControl of INTR1 external interruptionRising edgeFalling edgeBoth edgesI/O port functionExternal interrupt of INTR2 pinEdge SelectInterrupt FunctionPOS20 0101 1NEG201100/200Hz timer interruptRising edgeFalling edgeBoth edgesI/O port functionExternal interrupt of INTR1 pinEdge SelectInterrupt FunctionPOS10 0101 1NEG101External interrupt prohibitionφ L22INTR2ControlINTR1Control